I know this book is for twelve-year-olds, but I think it's really shitty that LGBTQ people were completely ignored. If your premise is that you find a magic machine that tells you who you will marry, and your main character is constantly commenting on other girls' bodies in a noticing-them kind of way, you need to at least have the possibility that she is a lesbian and that LGBTQ people exist.

Setting that aside, I hate my-dad's-fiancee-is-evil stories. It's been done.