Hairbear, here in the States, each state sets their own game regulations.
In my home state, Virginia, a hunter must be at least 12 years old (unless hunting on own land, OR under direct immediate supervision of adult hunter. Between 12 and 15, you may be an Apprenctice Hunter (less direct supervision). At age 16, you can hunt on your own.
You must be at least 18 to purchase rifles and shotguns, and ammo for same.