Who the eff cares. You only notice if you think about it too hard

Granny Smith told herself that Applebloom was Applejack’s sister (and not her daughter) so many times that she actually started to believe it.

@Background Pony #40C9  
Ahem, the show kind of gives the ponies human ages and progression. In the Canterlot Wedding episode, Fake Candance says that Pinkie’s ideas for the ceremony would be “Perfect… if we were celebrating a six-year-old’s birthday.”
 
That suggests the ponies age similarly to humans in Equestria. If we were going by realistic horse years, the ponies would be adults at the age of four. A Stallion is a male horse at least 4 years old, and a Mare is a female horse at least 4 years old. Going by realistic numbers, a 6-year-old horse would be too old for the kind of panty Pinkie was planning.

Dude, they are animated characters based on ponies. Stop trying to give them human ages and progression.@Wild Stallions

@Wild Stallions  
“How many years would pass before it was no longer considered a baby or juvenile?’
 
^ It really doesn’t matter because Lifespan =/= maturity. I doubt an elephant with a lifespan of 70 years takes 18-20 years to grow up.
 
If you focus on this for Spike then you have to consider the lifespan of a unicorn and pegasus, which is longer than a human’s. Would they mature slower too? And there’s still the alicorns. Is Luna still growing or not? Is the growth rate of alicorns the same rate as non alicorn ponies? Was Cadence an adult when she babysat Twilight? There’s just so many things too think about down this rabbit hole.

 
this is a kid’s show

Preety intresting, also in my headcanon i got some explanations like, Diamond tiara was born before her parents marriage or something related to Pear and Bright death with something magical that made Bloom staying in that state of filly for while or implied to incest or other stuff, because it is sick, Aj is Bloom mother or (even if it can be implified with former one, but in different ,of course way) she is older than rest of kids in her schoolhouse (which by the way is the only normal school here and also it doesn’t have normal classroom system, so argument like older kids should be in diferent class doesn’t work technically, in example of Snails and (probably) Snips (sure they’re dumb, but still), but also a midget or just a small

@Wild Stallions  
They definitely started younger than 10, but in “Forever Filly” Sweetie Belle reminded me most of a middle schooler, which would be about right if they started as elementary schoolers and then aged some.

@GenericArchangel  
Even that might be pushing it. I always got the impression that they were younger than 10. The only indication of them getting older are the voice actors own voices breaking. Remember when they used to call her Squeaky Belle?

@MadVillain  
Unless that comic is set after this episode. There is no way the CMC are that old without being fully grown, as it is they can’t be more than early teenagers.

@Wild Stallions
 
I think we all agree that dragons live a long time (seriously, if Dragonshy still means anything, they can sleep for at least a century), and that they may or may not mature more slowly (is Spike actually an early bloomer with the wings?).
 
Well, the latter is a bit more debatable maybe, but the former probably should be universally agreed.

@MadVillain  
Here’s a thought about Spike, how long are dragon years anyway? Lizards can live for decades. Crocodiles and turtles can live for over one hundred years. The oldest turtle was 188. Wonder what the lifespan of a dragon would be? How many years would pass before it was no longer considered a baby or juvenile?

If you want even more confusion added into this, consider the recent IDW 2020 comic which stated the rainboom that gave them all their cutie makrs happened 20 years ago meaning Spike would be 20, and according to this flashback Applebloom would have to obviously be older than Spike since she’s seen before AJ has her cutie mark. So in conclusion the CMC must be around 21-23 years old, which makes perfect sense.

@FlurryHboi  
haha its funny because the memer who shouts oof like a comedian doesnt give a shit

In my head canon, Ponville is just small enough to have students that are of different age in the same class, similar to the way it was back in small towns in the past. Just check out show ‘When calls the Herat’ and you will see what I mean. As for AJ begin younger in the first flashback and the same age in new one, well mistakes like that happends when show is running for long time.

@GenericArchangel  

 
Fair enough. Her reaction is certainly open to interpretation.

@Wild Stallions  
You said it yourself, we’re going on Granny’s memory, which has been proven to be… bad.
 
Final thought: I read “Sparkle’s Seven” as implying Apple Chord did, in fact, exist, with AJ uncomfortably blushing when Dash accusingly asked if it was true. The scene seemed to me to imply the story was true.

@GenericArchangel  

 
Where The Apple Lies implies that Diamond Tiara wasn’t born yet, and thus neither was Apple Bloom probably. The confluence flashback Granny Smith speaks of seems to line up better if it happened several confluences have past. The main issue with it of course is Apple Bloom being a baby and AJ being a blank flank despite being Current Bloom’s age. These errors could be choked up to Granny’s memory being in error and all over the place.

@Wild Stallions  
Assuming a moon refers to a lunar cycle is an assumption on my part, but why would they use moons to measure time if there wasn’t some cycle associated with them? And more importantly, we know the moon in Equestria cycles, since we’ve seen it both full and crescent. Once again, a moon equaling one of our lunar months is a guess, but under the circumstances a reasonable one.

@Frustration in Excelsis  
Here’s another thought. In what context does a unit of time, which normally corresponds to an orbital period, how does it apply in a world were ponies control the movements of celestial bodies with their magic?!

@Wild Stallions  
Sorry, you lost me. You assume AB wasn’t born yet as of “Where the Apple Lies”, a big assumption on your part. There is no reason to assume she hadn’t been born yet, for all we know she just stayed indoors the whole time where we couldn’t see her. That’s for more reasonable than assuming the Confluence before last lines up with “Where the Apple Lies” without any evidence.

@Wild Stallions  
The show has never used moons in a consistent way; “hundreds of moons” or “a hundred moons” are pulled out whenever the show needs a long time period but doesn’t want to commit to a specific one – Apple Family reunions happen every hundred moons as per “Apple Family Reunion”; the last confluence was a hundred moons in the past as per this episode; Luna and Celestia locked Discord in stone for hundreds of moons according to “A Rockhoof and a Hard Place”, but Discord describes the same timespan as thousands of moons in “Princess Twilight Sparkle”; the Equestria/nameless human dimension portal opens every thirty moons; and so on. There’s not really any way to reconcile the irregular use of moons in the show with any actually regular units of time. It essentially means anything and nothing by this point.

@GenericArchangel  
Actually, that’s making even more assumptions than I. We clearly saw that Diamond Tiara was not yet born in the Where The Apple Lies flashback and it is clear that she’s the same age of the CMCs. Applejack is a teenager in that flashback. If we’re counting in Confluences, that would mean there must have been at least two Confluences before the one depicted in Going To Seed. That seems fit better with what we already know.
 
For direct comparison, in the Pinkie Pride episode, there were twenty-one candles on Rainbow Dash’s birthadversary cake, at least that’s how many candles were visible. If the number of candles represent her age, that makes her at least 21 years old. On the other hand, if they represent how many years she’s lived in Ponyville, that means at the time of the episode Rainbow Dash had lived in Ponyville for twenty-one years, and it’s obvious she doesn’t live with her parents.
 

 
So if Rainbow Dash was 21 during Pinkie Pride and we’ve had at least four Hearthswarmings since then, that makes her 25 today and means the rest of the Mane Six must be about the same age. Maybe one or two years older or younger. If Applejack was 25 years old today, the last Confluence would have made her 17 (which would have put some either during or after the events of Where The Apple Lies), and the Confluence before that would have made her 9 years old. That seems to line up better with Granny Smith’s claim that the events of Going To Seed happening when AJ was Season 9 Bloom’s age. But still Apple Bloom’s appearance in it doesn’t work with the other flashbacks.
 
On the other hand, if the candles mean Rainbow Dash has lived in Ponyville for 21 years, then we must add at least 21 years to whatever age the Mane Six were in the Cutie Mark Chronicles episode. This is being conservative, as most kids move out when they grow up. Though, judging by her bedroom, I think we can safely say that Rainbow Dash moved out when she was still young. Maybe she moved in with Rainbow Blaze?  

 
That puts the Mane Six somewhere in their late twenties or early thirties. If Applejack was 33 today, the last Confluence would have made her 25. The one before that would have been set during or shortly after the events of Where The Apple Lies, as she would have been 17 then. And the one before that would have made her 9 years old.

@Wild Stallions  
I was countering headcanon with headcanon, in this case that the Confluence Granny Smith refers to was actually the one before last, with the previous one being “Applebucking Season” or whatever that episode was called. This explains Apple Bloom’s age just fine, and with fewer assumptions than you make.
 
Edit: bonus points for AJ’s comment on AB not hunting the Seedling since she was little. It makes sense to me because she would’ve been about seven or eight at the time, versus a teenager in S9.

@GenericArchangel  
You didn’t say anything about Applejack’s age, that’s what I was replying to. Going purely by the number of Confluences would mean Applejack is still a teenager. Realistically, if there was only an eight year passage of time since the Going To Seed flashback we should be within the same time depicted in Where The Apple Lies now!
 
You said ‘The problem is I measure time by holidays’. Thank you for bringing the issue of Confluences to my attention, but I don’t see how it’s a problem to my argument. If anything, it creates a bigger problem for Hasbro.