Even if you had your VCRA Defence sorted out to enable you to buy RIFs (which I'm presuming you don't at the moment?) then you really do not want a GBBr as your first ever airsoft weapon. It's been said many a time but a lot of people other than me, and for good reason. They're finicky, expensive to run and much more prone to breaking than AEGs are; the mags are also massively smaller in terms of BB capacity and they weigh about 5x as much. Unless you're thinking of the new G&Gs which would be more suitable for a newer player, but they're nothing like the WA/WE system rifles you'll have seen online in terms of how they look or operate.
Get your 3 rental games played, then get a good, reliable AEG. It's the best way to start out in this lark, as thousands of people before you have discovered.