Living in Secret by Cristina Salat

Ever since Amelia's parents got divorced, she has wished she could live with her mother and her mother's girlfriend, Janey, but a judge gave her father custody. Finally, after years of living apart, Amelia, and her mom decide there is only one thing to do. On a cold October night, Amelia's mother comes to steal her away. For Amelia, living in secret means changing her name, not going to school, and pretending she is twelve instead of eleven. The adventure of beginning a whole new life, with brand new family and friends, is marred only by the shadow of a past that could shatter the present in an instant, should anyone find out who Amelia really is.