I was exactly in your shoes a few years ago (I'm only 23). I ended up buying a Remington 1100 sportsman semiautomatic 12 ga. It came with a vented 28" barrel in full choke which is great for trap. A few years later, I bought a additional 26" barrel for it in modified choke for skeet and sporting clays. It isn't the prettiest gun out there, but I constantly beat shooters with higher priced semi's and O/U's. (I think of the 1100 as the ford truck of guns. There are better looking and more expensive ones out there, but it consistently gets the job done). I bought the gun used for $300 and the extra barrel for about $100. This gun has never let me down and doesn't recoil as bad as the O/U's so I can shoot for longer without tearing up my shoulder. My advice is to buy a quality low priced gun and when you get good enough, then save the money for a nicer shotgun.
Hope it works out and good shooting.
It matters not how strait the gate, How charged with punishments the scroll, I am the master of my fate: I am the captain of my soul.