I think this activity is more geared toward adults, actually. Kids participate, but the class moves kind of quickly, and many kids have a hard time following along. I did the class last fall with my kids (9 and 10 at the time). The older one kept up pretty well until towards the end, and he basically said "screw it" and turned Rapunzel into a vampire. The younger one got lost quite a bit earlier, and just gave up. Certainly, I saw kids who were really into it, but they seemed to be kids who were either good at drawing to start or not overly concerned with perfection.
The class itself is quite informal. It's in a corner of the lobby at AoA. People sit on a bench or the floor and have clipboards and a pencil while the CM's drawing is projected onto the TV for everyone to follow. My guess is the class size and makeup can vary widely from session to session.