Well it's a superhero show, so it has plenty of action. Also, they look young because again, it's Horikoshi's art style. You know, like how Ohtaka's art style (Magi) makes the males look female, or how Kubo's art style (Bleach) makes characters look very human. All of the characters are actually in high school, so fourteen-eighteen years. And it's also got a lot of Comedy to balance it out, like this here X