21
Three.
The state of Illinois does not issue carry permits, so it's illegal at any age to carry a gun in Illinois, assuming you mean out in public with a gun permit.
In PA you have to be 21 to conceal carry (or carry loaded in your car) a handgun.
18 to purchase
AFAIK, no.
You must be 21 or older.
Guns are illegal for any age in England, unless you are a police officer.
18+ but any age to wield it
You will have to define what you mean by carry, and which gun. There is a large difference between carrying a concealed handgun, and carrying a rifle or shotgun when hunting.
What kind of license? Where are you? What kind of gun? to carry a gun north America pistel It depends on where you are. In some states, you have to be 21 but in a few, you have to be 18.
It depends on where you are and what you mean by gun license. If you are in the U.S. and you mean a permit to carry a gun, check the related link for information.