The same rules don’t apply to immortals the fact that you’ve lived for well over a thousand years doesn’t change the fact that you have a tiny pubescent body and the fact that you’re drinking blood as opposed to alcohol makes it worse, not better considering that both are technically poisonous but alcohol at least is more likely to be sterile, whereas blood could contain any number of std’s and infectious pathogens, not to mention that you as a humanoid/alicorn herbivore have liked never evolved to drink blood and probably shouldn’t unless in the unlikely event that you’ve become a vampire, which I don’t suspect is the case but seems befitting of the princess of the night.