Being a teen

I'm a teenager and all of my friends have flat stomachs and not too big boobs (A's) but I have skinny arms, legs, face, anywhere BUT my stomach and chest. I feel like I shouldn't have to try and fix this problem, like I should be like all of my friends. The thing is I'm not. And I don't know why! I just can't figure it out! Especially because I do so much sport too.