Welcome. We have quite a few current/former paintballers hanging around here. They tend to do very well in airsoft as well. Just remember, the ranges are way longer than in pb.
Anywho, there's a game out at Four Peaks on Saturday you can still get in on. They're in need of a few more green players (players wearing Woodland, ACU, Multicam, ect.), but if you have tan camo (desert camo, ATACS, ect.) you're still more than welcome. It's a bit of a drive if you're in the South/West Valley, but it should be a good game.
Alternatively, (as BadCompany said) there's Fighter Town on the west side. Great field run by great great staff. Games are pretty big on Sundays every week, but the Saturday game this week seems to be attracting quite a few people. At $15 + tax for all day, you can't go wrong. Just remember a barrel sleeve and some bio BBs and you're golden.
In addition, keep an eye on the Local games/RSVP board. There's usually a game or two posted every month when the weather is nice. They range in location from places 15-20 minutes away (Hatfield, Four Peaks, ect.) to halfway to Tucson or up on the Rim.
Again, welcome and hope to meet you out on the field.