Pre-teen girls are in the developmental stage of how to have less dependence on their families. The typical behaviors that parents will see are less time with family and more time with friends. While they are pulling away from their parents, they need to depend on someone. They are going to turn to their social group. You will see them spend more time on the phone, more time on technology with friends. They are also going through a lot of changes. This can make them have a big preoccupation with their body. They may spend more time in the bathroom, more time looking at themselves in the mirror and all the changes that are going on with them. Also, you may notice changes in their mood. This may be related to their brain development, and some people have that as hormonal development. But whatever the reason, one day you may see your child pouting and complaining and arguing with you, and the next day, they are bouncing around the house happily. Don't be surprised at some of these changes in your child. The most important thing you can do is provide a structure and stability that they need among all these other changes that are happening. When they come home, they will feel like this is the one predictable, safe place in my life.