Molly by any other name

This book is really good. I just finished it. It's about a girl who is and adopted.... and she wants to find her birth parents. Her parents who adopted her are really nice, but they don't want her to find out because they're afraid she'll give them up to live with her other parents. She tells them that they shouldn't worry, but they don't listen. Finally Molly goes to a society which helps people find their real parents. A girl named Mary agrees to help Molly. Then they find her mother, named Karen.... Molly meets her and they like each other. Her other parents are really upset, but they agree that Molly can just be friends with her birth mother.

This book ends with Molly becoming a cheerleader which is really random and weird.