I don't think the average age of the forum populace will necessarily reflect that of Graal Classic, given that I see tons of 8-12 year olds around Graal city. But, on the other hand, I'm happy with the results so far. I can't stand it when some 11 year old tells me that this game is intended for children. Of course we all know that's not even remotely true, but it bothers me nonetheless.
I'm 26 by the way.
(Oh, and I have nothing against the younger players of Graal. I've met lots of younger people who I get along with very well. And it's more about maturity than age, anyway)