I have a 13 yr old and I can relate to what you are going through. I try SO hard to keep my mouth shut and let her work out her differences. I know it is a ton of girlie stuff and the girls are changing daily. I learned to never speak badly of any friend becauase that friend might be the best friend the next day (or hour) When speaking with another mom, it is only mentioned casually. I always say, I know my daughter is no angel and not perfect but....
One thing we keep reminding ourselves is....when 2 rough stones keep working together, they end up smoothing each other out"
This is hard to do when you are the one with a child who gets hurt. I happen to have the house where everyone comes, every weekend. I have no issue with that because I keep tabs on the girls here and I know what they are doing. However, it would be nice if my daughter would be invited over to other friend's homes more often. She is invited occasionally and that is nice. Most of her friends have siblings and my daughter is on only child.
We are dealing with girls being mean right now as in calling names, etc. My daughter is strong willed and I am not going to squash that aspect of her personality but she is also very sensitive. They talk about each other behind the back then they call my daughter on Fri to come over to our house and they will stay til Sunday! I've come to find out that some of these girls have other motives for coming to my house as in .......blockbuster movie night, cinemark movie night, dave and buster night, etc all at MY expense. We have nipped that in the bud.
Good luck sorting through this. Congrats as a teacher. I substitute teach and you will see a lot of this behavior starting around the 4th grade.
Susan