Bolt action sniper rifles are NOT a good first choice of gun. It's a specialists tool for a specialized role. Its advantages only shine once you've already mastered camouflage, marksmanship, gun tech and teamwork.
Most stock bolt actions total shit, upgrading one to be competitive on the field takes a substantial amount of work and cash. The most important improvements are not just drop in upgrades: they are permanent modifications involving lots of cutting, drilling and sanding with huge potential for failure.
I'd recommend running an AEG for a year or two, get good at using it, and when you have the chance ask a friend or teammate if you can borrow their bolt action for a game. If you like it, start doing your research because this stuff takes a lot of work. I wrote a huge post on the subject of sniping
, read it if you want to get a basic idea of what to expect.