/ic/ - Artwork/Critique

I'm in the very early stages of character design for a comic I want to make, the issue being, the main character is a 12-year-old boy, and I don't have a lot of experience drawing kids.
The design is not erotic really, he is supposed to be noticeably fit for his age but not Baki level shit, believable at being noticeably fit for his age.
He's laid back, and rarely get's stressed for anything, he's somewhat pretentious, just a little bit of a perv but doesn't want to hurt anyone.
Yet, when he actually manages to get scared, a rare sight, he can get surprisingly fragile and nervous.
Do you guys have any references, or similar characters you can recommend, or tips, like height or similar styles?