Character model - critique wanted

Hello fellow artists! My first post here and am hoping to get some critique on my progress. We learned very little zBrush with my last degree, but found to be needing it with my current job. We only have 4 people in the room where I work and I’m the only illustrator who knows anything about modeling. So I was hoping to get some help here.

The character is a light skin African American boy. This is geared towards middle school students. I haven’t focused much on polypainting/color/material. Just trying to get the model to look right. I’ll attached my 2d concept drawing and my turn around sketch I used for reference. Once I get him more solidified I have about 9 more characters to do and will use him as a base for the male characters. The plan is to later take these into another program to rig and pose, possibly for animating in the future. Any help or tips would be greatly appreciated, thanks.

Turn Table: [youtubehd]xfA5pPJvznc[/youtubehd]