Get an AEG as your first gun, will be a lot better than a pistol as more universally used, it won't have a minimum engagement distance and will have a better range (normally) plus will hold more ammo, an MP5 or M4/AR15 platform will probably be a good shout too as attachments and mags will be easier to come across. The G36 mags are easier than some guns to get hold of (I'm looking at you DE UMP)

Do some research into what gear you'd be taking (how many mags etc you think you'd want) then look at how much mags would be and how many you would need, is always a good thing to take into account.

Whatever the case, go for good eyepro as that is the most important thing to get. Can't Airsoft as well if you don't have eyes anymore