I started debating on the 'net at 15 (in Dawsons Creek, heh) and it was the best way for me to learn. If you're surrounded by rainbows and sparkly shit its an even bigger shock when you go to a forum and are ripped apart. The debate that's on Boolprop was simillar to the debate I faced against the other adults and I never had an issue keeping up with them.
I think assuming the younger kids can't debate is quite insulting to them.