Inferiority complex?! Whats wrong with me?

Your a young guy, you will find your forte, maybe tomorrow maybe later in life, but don't take it as an failing on your part if other people have done well, you can't control that. I went through school being at best average or less, when I was 21 I was accepted by MENSA, it surprised the hell out of me! believe in you my friend there's no one else quite like you on the face of the Earth, and try your best to be the best person you can be, don't let your size influence how you feel about yourself its utterly irrelevant. In addition at your age your intelligence cannot decrease only increase, so have faith in yourself and trust me I know what I'm talking about. good luck