Glad to see everyone got things straightened out.
Some tips: 00 Buck loads fill body bags. Birdshot, regardless of what most people say, just makes nasty not usually fatal wounds. I've seen two guys hit by birdshot. If they'd intended to fight in the first place (they were attempted-murder victims) they would have continued to, but the shooter ran off. The shooter in one case used a Winchester 1300 with a 28" barrel from less than 10 feet, fired twice and hit the guy in the arm and the leg. So much for aiming eh? The other guy fired once from a NEF single-shot, and made a grazing body shot, the vic got peppered bad but very survivable. At VERY close (5 yards) birdshot with a proper center-mass hit will do the trick, but past that, I stick with 00 Buckshot.
C-W if you're 13, get the Bantam-stock model, or you might not be able to pump the action. Don't overload it with accessories either. A 6-shot Mossberg 500 with 18.5" barrel and a fiberoptic bead was my first shotgun, and for anything inside 30 yards, that'll do the job just fine. Maybe toss in a stock shell carrier and a light, and you're done.