Sniping is more of a mindset than hardware. There's a lot of sitting around and waiting, crawling, and sneaking around. It's not for everyone.
My advice is your first gun should be an AEG, something you can play in any scenario. Get a few games under you belt first and meet people. Sniping isn't generally a role for first time players.
If you're in our area, attend one of the
Sniper Clinics and find out if it's really for you.