Do non-celebrities count? If so I'm 25, and the last person who guessed my age (This was after shaving, mind you) thought I was 16.
Funnily enough, as a Manager at my local Wal-Mart, when I have to override something, or tell a customer no, they almost always throw a fit saying either: "I'm old enough to be your grandmother/father, I don't have to listen to you. Go get a REAL manager." or "I'm not listening to some brat whose balls haven't even dropped!" First one tends to be older people and the second one came from someone who was 17 or 18 at the time.
Funnily enough, as a Manager at my local Wal-Mart, when I have to override something, or tell a customer no, they almost always throw a fit saying either: "I'm old enough to be your grandmother/father, I don't have to listen to you. Go get a REAL manager." or "I'm not listening to some brat whose balls haven't even dropped!" First one tends to be older people and the second one came from someone who was 17 or 18 at the time.