God Help the Child question

Hi! I read this book a while back and I just can't seem to remember the title! It's about a girl who is mistreated by her parents and her sister, but one summer her grandmother and her cousin takes her on a trip around the world and she comes back confident and no longer a push-over. She became hot and starts flirting with her dream guy next door only to realize she likes his bad boy little brother better. Their names might be James and Kyle. Her parents turn out to not be her real ones and there is a bunch of drama.
Thankful for responses!