I took a virgin (STRICT) Mormon girl who would blush and tell you not to be crude if you used the WORD "sex" in a sentence, let alone talk about the topic itself and turned her into a total sexaholic nympho. It can happen. It takes time- it takes PATIENCE- it takes understanding (and in my case, actual love
). Go slow. TALK. Really.
In your case, she most likely was taught at an early age that sex is bad, it's dirty, etc., more specifically that sex purely for pleasure and not for procreation (read: religious nuts) was wrong or bad or dirty or slutty, etc.