Good news: Maryland does not regulate the sale or possession of long guns. Therefore, you do not need a "gun permit", (whatever that is) to buy a shotgun, but due to your age, you may need to have a parent or guardian buy it. They may have to supervise your use of the gun too, until you are older. If you intend to hunt, you will have to take and pass a Hunter Safety Course before you can buy a hunting license. Look here to see Maryland gun laws.

http://www.nraila.org/statelawpdfs/MDSL.pdf

IF you intend to be a gun owner, hunter, or shooter, you need to join the National Rifle Association!!

Good luck, have fun, & be safe!!