Gonna be honest here, I don't think it's as good as people are saying it is. Your lines are shaky, which makes the whole thing look somewhat childish. Those random black lines on the hoodie (are those supposed to be folds/creases? that's not how they work) look odd and so does his expression. I can't tell if you were going for scared or angry. I know of a good tutorial on drawing expressions, if you like I'll PM you the link.
Don't be discouraged though, you'll improve!
