I know how that feels! Just after my 17th birthday, I went to Costco, right? And you know how they give out food samples? Well, I wanted a sample of cake. So I go to take some and the guy who's giving them out starts YELLING at me. He's like, "Where are your parents!? Kids can't take samples without their parents!" And I must've given him a weird look, cause a few seconds later he was like, "How old are you?" And I was like, "I'm 17!" He replied with, "Oh, you look much younger."
I was completely crushed by that incident. I've always thought that I look young for my age, but not so young that I'd be yelled at when trying to eat food because I might be too young to not know what allergies I have! Oh well, when I'm 40 people will (hopefully) still think I look young.