18
At paintball fields, or on your own property.
No.
There is no liscencing for paintball guns in the US.
18.
There is no background check required for paintball guns.
You shouldn't be playing paintball if you can't figure this out on your own. Alright?
Yes, they do not do a background chek when you order one.
No, in the US you must be 18 to buy paintball markers and most accessories.
The purpose of a paintball gun is to fire paintball pellets, to mark opponents in the game of paintball.
You must be at least 18.
A paintball marker is a paintball gun. It is just called a marker instead of a gun.