Now that you have a gun, as everyone mentioned propper eye protection should be first on your list. Most fields require sealed googles so check with your local fields prior to purchasing something. However, eye protection is one thing you should never ever cheap out on.
After that more mags (because HiCaps suck imo) and then some kind of chest rig to carry said mags. BDU's arnt super important but helpful. I do recommend a good pair of boots over BDU's. I was in shitty boots two weeks ago and stepped on a rut in the road and my ankle gave way. The boots had zero ankle support and I was very lucky that I didn't snap my ankle. If your in the middle of a field and roll your ankle its a long walk back to your car. I swear by my Danner's or Magnums.