Have you graduated high school yet?
I'm 23, and don't believe I look any older or younger. When in uniform, I try to present myself neat and professionally. However, I'd say once every couple of weeks, someone looks at me and says, "Are you sure you're old enough to be flying this plane?" For those of you who get the same question, what are your favorite replies? Here are two of mine.
"Oh yeah, its ok. My permission slip is in my flight kit w/my moms signature."
If the captain is with me, i'll look at him/her and say "Oh, its take your kid to work day."
What wise ones do you have?