Your local police can give your correct and current information.
Since you can access the internet, look up NJ gun laws and find out.
You need to tell us more about the "gun license" and for what area. There are many different gun licenses.
You have to have a valid fishing license in kansas at 16
Whether or not you can have a gun license at 20 years old depends on which US state you live in and the type of gun as the laws vary somewhat.
21
No.
As far as I know you have to be 18 and of course, be able to prove it with a valid drivers license at the time of purchase.
That depends on if your state requires a license or not. Most do not.
Old enough to spell license.
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.
You must be at least 21 years old to sell alcohol in the state of Kansas.
In Kansas, you must be at least 18 years old to obtain a piercing license.