1) No, because if it's fun it's probably illegal or regulated. Sure it's a bit of a tongue in cheek statement but there's some truth to that
2) Most fields are 18+ but there are some that will allow 16+ or have open age limits. It all depends on host/admin and the field owners as they have last say.
It all depends on where you end up. I don't know of any places out east that minors can play at but out west there are; FVAA/Big Foot (Fraser Valley Airsoft Assn), EASY, Low Shotz, and Ambush Anonymous. I'm sure there are some out east but I don't know them since I don't really know much about the landscape of things out in the east.
In the end though it all boils down to liability and hosts not wanting to be baby sitters (sure your parents could give you ten bucks and tell you to go to the mall or w/e) but because you're a minor there is a different dynamic which includes the concept of "due care". Also waivers don't always cover everything and make it water tight. It only acts as EVIDENCE it doesn't relieve owners/hosts of liability. If there's a history of non compliance to rules stated in an insurance policy (ie. lets say allowing MilSpec ballistics to be used when it clearly states ASTM rating only) the field owner could be liable. So basically it's to cover their ass.
ಠ_ಠLess QQ more Pew Pew
READY TO >> RACE