Honestly best thing is to play quite a few games and feel a few guns on the field. I have yet to see a player not lend another player their rifle prior to a game starting... honestly in a couple of walk-in days hopefully you get to try a little bit of everything and that will help immensely in narrowing down options.
I always recommend an AEG rifle to start, especially something in the AR15 (M4 etc) realm for several reasons. Everyone has or did own one, the version 2 gearbox arguably has the most parts available and magazines will be plentiful in games (run out of ammo? np buddy will toss you his mag to keep you in the game). Also electric is way cheaper to get into than gas.
That will more then get your feet wet in the hobby and allow you to see what other creations you want to add to your arsenal as time ticks on. I started with a gun 2 years ago now I have 7.... :/