I'd say wait untill youre 17 then take them out to a game let the game org or a player talk to them. Let him explain all the stuff that needs explaining and make sure he explains that the police cant shoot you just because you have a gun in public you have to comply or they can't shoot at you.
The player/org should explain everything fully and make them feel more comfortable about owning the airsoft.
Another option would be when youre 18. Either still living in your parents house or in a apartment/dorm then you buy it. (Be careful your parents might not like the idea of you having it in the house even if you're 18 and they might kick you out. But they love you too much to kick you out right?)
Next year join the reserves and show your parents you're responsible. Some people in the reserves play airsoft so you can get you're parents to talk to them. Plus they give you free CADPAT.
ಠ_ಠLess QQ more Pew Pew
READY TO >> RACE