I just thought that maybe you'd know being as you're both from Azeroth! I can look at a human and tell if they're old or not based on how they look. I can do the same with Moroi, not to mention my own race.

There's no delicate way to ask someone from another race how old they are and what exactly that means in the scope of their racial lifespan. Where I come from, people are lucky to live past a hundred years unless their evil undead assholes.