I had to laugh when I read your post! (sorry! laughing WITH you, not AT you!)
I used to say that the morning my daughter (will be 23 in a couple of weeks) turned 13, she woke up and her head spun around a few times, and she spewed pea soup!
I think this is part of God's plan to help us let go of our children. (you sure are ready for them to go to college!)
The best advice I can give is to say, "this, too, shall pass!" My daughter and I are good friends now...for about 2 years. Prior to that, it was just one fight after another.
I do think that it is important to stand up for what you believe is right, that being said, you have to pick your battles. With my daughter, everything I said created a battle! (I was always wrong, haha!) There is SO much drama at that age and the pressure is tremendous to fit in. I think the consequences of poor decisions are greater than when i was that age.
Try to find an area of common interest that is very important to her...my daughter took dance and was very involved with that and with several choral groups within our school and county. Also was involved with our church youth. She knew I was proud of what she was doing, plus I enjoyed watching her so much. It gave us a bit of common ground on the battlefield of the teen years..
Mostly, they know you love them, and no matter what they say to you or how mean they are to you, you will never stop loving them. You are the ROCK in their life. (not that they would ever admit it!)
Keep praying!