If it's not on facebook you're not going out. until she sends you a relationship request you don't really have to say shit. you can always us the to famous lines women use all the time. "I think were moving to fast", "I just need more time to think". Point to note a women will use you just the same so keep that in mind. worst case scenario she gets pissed off and breaks it off. If you only want her as a fb then you're not that into her and can accept that.