Morals are like sand dunes with lots of dune grass growing on it.. the more grass the more the dune can withstand the waves and wind and no flooding of the town will occur. No dune grass, and the dune is washed away and the land flooded, homes destroyed. In the same way, as Christians it is imperative that you live around other Christians. We are not to tempt God and put ourselves in morally dangerous fields. It is a fallacy thinking you an go in by your own accord and convert non believers- don't do that! It is a sin of pride! Remember Jesus said "Do not give dogs what is sacred; do not throw your pearls to pigs. If you do, they may trample them under their feet, and turn **and tear you to pieces.**" (Matthew 7:6) A three cord ply is not easily broken. One cord... yup!
It may be OP that your daughter is just as clueless as I was in morality, despite the catholic upbringing or it may be that she has decided that its 'no big deal'. Either way, she will find out what her personal choices procure. Perhaps OP you should just have a loving calm discussion with your daughter about it. Don't push or pry, but just see if she is open to discussing the matter. If she is clueless, like I was, it may help her understand this is not a wise decision.