The age can fluctuate. It's probably easier to be older, because you don't have schooling constraints, especially that of homework. However, if "hardcore" are the kids who play Halo 3 for 8 hours a day, then probably 16 or 17. Real hardcore gamers don't really have an average age, IMO.
My Games of 2011:
The Legend of Zelda: Skyward Sword
Elder Scrolls V: Skyrim
Super Mario 3D Land
Uncharted 3: Drake's Deception







