I had a hard time "getting into" this book. I think it was because it was written in the first person. {As a kid, I used to automatically discard any book written in the first person.} 
 But I persevered with this book, because I set myself a goal... and as it turns out, the book was worth it. 
 I don't remember hearing about a twist at the end of the book. I did guess half of the truth about half way through. But the author's skill and the way she crafted the story kept me from seeing the whole... 
 Without giving anthing away, all I can say is... finish the book. You won't be sorry.