No parent is perfect; we all can look back and think of things we could've done to help our children be better prepared for adulthood. And sometimes it's best to admit it to them and encourage them to learn from our mistakes.
But ultimately your daughter alone is responsible for the decisions she has made. You tried to teach her the difference between right and wrong when she was younger; you did so both by your words and by your example. But now she has willfully turned her back on all this and chosen to go her own way. She isn't a puppet or robot; she has a will of her own, and she has deliberately chosen this path.
The problem is that this path will only lead to heartache, insecurity and tragedy. Satan always promises happiness -- but his promises are a lie, and eventually your daughter will reap the tragic consequences of her rebellion. The Bible warns, "The one who sows to please his sinful nature, from that nature will reap destruction" (Galatians 6:8).
Pray for her, that God will open her eyes and help her see she's on the wrong path in life. Also, in whatever ways you can, let her know you still love her and care what happens to her, in spite of what she's done. And remember: God loves her even more than you do, and Christ still has the power to change her.