You mentioned that a lot of users would be kids. Do you feel that the tools you have here are appropriate for all kids? What age groups do you think this would work best for?
Unless I missed it, is there a way to get to the next lesson without having to go back to the homepage? That might help with navigation for some users.
I know first-hand that editing on Wetpaint can be frustrating at times, but personally these pages are very compacted with information and a bit difficult to follow because of it. To a novice user, this could be a turn off.