Well, back on topic, his proportions are rather off, and that's without including the eyes. The head is very upside-down candy corn-shaped, if you understand what I'm getting at. For how big his ear is, you would probably expect to be able to see at least a little bit of the other one.
Now for the eyes, if your intent was to make him look young, there are plenty of other ways to do that than making the eyes gigantic. I actually don't think he looks young at all, but more like an actor that I can't name right now (the actor is not young). If you're going for young, then fatten up the cheeks some, make the mouth bigger, and reduce the eye size a bit. Color the whites in, because otherwise he'll just look like a "straight-up alien," especially with pupils and irises that big. Krillin gets by as normal looking because his eye parts are smaller.
The hair, for the most part, is done okay. However, in some parts the hair looks like it's coming out of the bandanna rather than the scalp (that middle section where there's a break in the bangs especially). Also, this kid has a horrible wedge cut. Add some sideburns and some hair above the ears because like the mullet, the wedge is just not okay.
I'm probably not one to complain about this, but your lines are a little too fuzzy for how crisp you colored. If you're using Photoshop, read a tutorial on how to use the pen tool so you can have some actually solid-looking lines.