All I can say is to let your child try it out for themselves. IF it is too "over the edge", they can go back to the Lab. Same thing for 8 yrs and the club. BUT just remember,if they choose the younger "lab, club or even nursery, they will be entered into the system as that age group and not their "official age". This happened to us on our Oct.16th 2004 crusie. My 3 1/2 yr DS went to the club with his older sister and decided he felt more comfortable back in the nursery with his younger sister. (I must also add that he remembered the nursery "manager from our 2002 cruise,how I don't know but he remembered Tracy). They said there was no problem for him to come into the nursery. But once they put him into the system as a nursery child, he wasn't allowed to go back into the club for activities (which suited him fine).
Also, if your child wants to play on the computers instead of one of the activites, I was told by the counselors that they could. I know my 5yr DD wanted to use the computers instead of "the nightly movie". She was allowed to do so and she LOVED the club. This is the same for the lab as well (at least that is what they told me).
I do know that on our cruise there were a group of teens that I thought we "acting older" then what thier age actually was. One girl had a figure that most 20 year olds would kill for. I know as a parent, I watched her and her actions with some of the boys and I would be alittle "nervous" if she was around them.
Also, there were several nights that the stack closed LATER then the adult clubs! One night it closed at 2am. Sessions closed at 12am and the other two closed at 1am. This to me is not right!
Just my two cents!