Greetings From Witness Protection by Jake Burt

My name is now Charlotte, although you might remember me as Nicki. I always dreamed my real father would rescue me from foster care after his release from prison, but I now find myself living with the Trevor family in Witness Protection. If I ignore the fact that my "mom's" brother wants her dead, it's a nice experience. My new brother hates me joining the family, but my presence is supposed to help keep them safe. I still get the urge to steal things, but that's usually when I'm nervous. I'm getting good at being Charlotte, although I hate that no one can know the real me. Even my new parents didn't read the file about my past. 

Found this book suggested in a Goodreads reading group, and it was a pleasant surprise. Charlotte reminded me a bit of Gilly in The Great Gilly Hopkins, although Gilly was much more mischievous. Foster kids are often portrayed as sad and angry, but Charlotte didn't cause trouble and was upset after learning she shouldn't try to earn good grades or excel in sports. Most of the story sounded like a common situation where a child joined a new family, even though Charlotte adjusted better than her brother. She was easily accepted into the new school and became good friends with Brit, a seventh-grade outcast. Char's efforts to help this girl were especially endearing and honorable, as she wouldn't abandon Brit. It was a normal middle grade novel. However, the danger of an assassin was put on the back burner until the author slowly dropped hints that the uncle was still plotting revenge against the mom. These reminders created tension in the plot until it became evident the assassin's attack was imminent. It's nice to have books with happy endings, and this one ended as happily as it could. Overall, the story was very entertaining, and I recommend you give it a shot.