Is she Catholic? If she is, then you can try to naturally work some things into your conversations (depending on how close you are to her). For example:
You: “You know, I’ve been Catholic for “x” number of years and I always knew sex outside of marriage was wrong, but I never knew why. I just read a great book that finally explained it to me! It feels so good to know the reason behind the teachings and to be assured that the Church isn’t trying to stick it’s nose into my bedroom but really has my best interests in mind”.
Sorry, lol, i guess that wasn’t so “natural”:o , but you get the point…
If she is not Catholic, you could take the same approach but it wouldn’t lead to the same place.
None of my friends are faithful to any religion and neither is my family (parents, sister, grandparents, aunts/uncles etc) so I constantly feel the pressure of being the Catholic “example” and I fear that if I mess up there will be a round of “I told you sos”… it is tough. I find it hard to explain my faith and all of the “rules” without sounding condescending or arrogant. I try to ask the Holy Spirit to help me when I need to speak up about my faith.