The shotgun you have would be a good one, whatever it is. Don't get trapped by the idea you have to be breaking q00 straight by next week, use your present shotgun and have fun. After using it for a while, you'll have a better idea of what needs to be changed to suit YOU, and proceed according.
Of course, if you've no shotgun at present,try the Remington 1100, the Beretta 390 and 391 series(Never owned one, but folks whose opinions I trust use them)or peruse the used gun ads on the BB at your local range.
If you like pumps, and don't mind the slight disadvantage you get with one, the 870 Remington is one of the best shotguns ever made....