Don't go overboard on buying a gun for skeet if you are new to the game. Any field-grade shotgun (pump, semiauto, or O/U) will be fine, just make sure it has an IC or an open cylinder choke. A gun which uses choke tubes will allow more versatility. And a shorter barrel, say 26", will be advantageous. It should fit you properly, so try a number of different shotguns and pick one which feels good and balances well. One friend of mine who was an excellent skeet shooter used only a pair of cheaper Mossberg 500 field grade pump guns, in 12 and 20 gauges. O/U guns are fine, but will be more costly. Most shooters will do as well with a 20 as with a 12, and some do better. I always reloaded my own shells, and for 20 gauge, I used 3/4 ounces of shot. Those worked fine. For 12 gauge, I used 7/8 or 1 ounce, usually the latter.
If you really like skeet enough to keep at it, you can always upgrade your shotgun when the time comes.