I disagree, IMO if you're under 18 your airsoft use should stem NO FARTHER than shooting targets, not at anyone else. Turning 18 does nothing to most people, but at least at that point they are LEGALLY responsible for their actions and things are treated more seriously.
Too often, and in too many places, I see small kids w/o a clue (or a caring parent) shoot at eachother (w/o eye protection), at peoples pets, houses, cars, etc. Yelling at them only gets them to change their location, and so many young'uns these days could give a f'k less about what an adult says - they have NO respect and would sooner give you the finger than turn over their guns and tell you where they live so you could talk to their parents...
I had many bb guns, nerf guns, dart guns, etc growing up, but at NO point was I EVER allowed to shoot at another person, and if I even POINTED at another person the inside of my room would be all I'd ever see again. It takes a certain level of maturity, RESPECT, understanding, and unCOMMON sense to play airsoft. If yer under 18, shoot paper circles, turn 18 - be responsible, or go away and never touch a firearm OR replica again.