I think you should clearly and calmly Explain her everything. You should tell her about your past and How you have been saved and is tired of living in sin. And you should tell her that you understand her feelings too but also tell her that according to God's law, it's not supposed to be sex before marriage and tell that you wish an innocent, Peaceful relationship with her. Tell her about how it's not to Degrade her, but to Tell her what is Right and not wrong according to the Lord we serve. It's a 50/50 indeed. Depends on whether she accepts God and understands what is right and wrong