purchasing your first Rolex from Craigslist with not much knowledge about Rolex....what could go wrong?
Even if you got a genuine watch, you'd have ABSOLUTELY no way to tell, it could have fake non-rolex parts on it, it could be stolen so when you service it it is never returned to you, it may stop running in a day since the movement could need $1000 in repairs, they could show you pics online of a gen watch and show up with a fake ringer that you'd have no idea to authenticate, it could be completely fake, they steal your money, etc etc.
Go for it.