So, usually that’s what I use interviews for. Sometimes on the application I ask for an age range. Usually like “13-14, 15-16, 17-18, etc.” then use the interview to verify by the sound of their voice it’s not super accurate but you can usually tell a young kid who lied about their age vs. someone older.
I never ask about personal information aside from their first name and that’s always optional. The only reason I ask for a first name is just to allow myself to get to know them a bit better and actually refer to them by name when applicable.
I personally don’t usually care about the age of my moderators. As long as they are willing and able to do their job correctly and effieicnently it’s all good. That being said, the average age of my moderators is like 15.