The first thing I (along with many others) would suggest is you get Age Verified. Once you meet up with an AV Rep and prove you're over 18, you'll get access to Retailers and the Classifieds where you'll be able to get any gun you want.
Most rental guns will be some kind of M4/MP5/AK variant. I also suggest you continue attending games as you can get an idea of the different type of rifles/SMGs/pistols out there. Ask nicely and people will even let you handle theirs to see how it weighs and feels.
I think the first step for you is to try out what type of model you like/feel comfortable with. Go down to a local store and ask around as well. Personally I started with a G36 as I liked how it looked and it felt more comfy.
Once you've got a type of gun figured out, it'll be much easier for us to recommend brands and availability (AV required)
H&K G36c (KWA) / Glock 18c (TM) / Kimber LAPD SWAT Custom (TM) / Mossberg M500 (ACM)