While it's not illegal to own them under 18, I also don't think that 14 year old kids should be allowed to use airsoft guns without supervision. And the community rules state there's no playing airsoft under 18. So no reason for a 14 year old to own them. Besides, I can bet the OP's "airsoft" guns are from Canadian Tire or Walmart anyway. Even if there was a place that would let him play, he'd be laughed off the field.
BTW, I should add that my son is 9 and has 2 AEGs. But they're in my posession, and he only gets to use them when we're shooting together.