How do I avoid statutory rape charges when I'm innocent?

Well I'm 21 my ex was 15 but had mother's consent and I have proof saying so her mother contacted mine and said it was fine and text to prove. But threw out the relationship she would lie cheat have sexual intercourse with others then the man finds out, you ask her she breaks up with you and tells you if youu contact me again my parents will press charges so I dont contact her my phone breaks I block her off everything.. by then 2 months later she messages ypur new girlfriend and says well I'm pregnant with his child and then goes on to say nonsense like threatening my gf saying I hope u die and choke on own blood and so on and so forth. Test says that she is 3 weeks pregnant. We've broken up months ago.