In states that require them, it is a license to own (not to carry concealed) a gun.
You need to define the term gun license. In most of the US there is no license to own a gun. Some states require a license to carry a gun. others to carry a gun concealed. There is also a license to make or sell guns. All are different and have different procedures.
It depends on your state laws. Some places require a license to buy, others may have a license to carry concealed, some do not require a license if you open carry.
No if the gun is not registered in your name , no you can not own a gun. if you do not have license to own a gun you can not have it either
No.
No it's not necessary.
You don't need a gun license if you are 25 but if your under 25 you do need a gun license
Sporting goods store or gun shop. I depends on what you mean. If you mean a license to own a gun, in the U.S. you don't have to have one, except in a few states. If you mean a license or permit to carry a gun, you normally can't get that at a gun shop or sporting goods store. In states that require training to get a permit, you usually have to go to a certified training school.
It possibly depends on the locality. In most U.S. states, there is no gun registration, so no, it won't. In Tennessee, a police officer can request to see if you have a gun carry permit when they run your Driver License number, but they can't check to see if you own a gun.
In New Zealand you have to be 18 to own a gun licence.
No.
If you mean in the U.S. it depends on state law, but also, what you mean by "gun license." Each state sets its own requirements for issuing handgun carry permits. Most states do not require a permit for owning a handgun.