Meh.

This was not the book for me. The writing left me nonplussed, the characters felt two-dimensional (even though they all supposedly grew because of this experience), and the author got so many things wrong about XP.

Here are my gripes:
1) XP is so much different than the author writes it. It doesn't come into force because of a "triggering event", and if that was how it worked, then Katie's 6 year old self's sunburn would have triggered the disease then. XP is always present.
2) People with XP don't live like Katie did. Not at all. Go read a blog about it. Thousands of people have XP around the globe. Or if you want another author's perspective on a character with XP, read Seize the Night by Dean Koontz. Chris has XP in that book, and I feel like his condition is more realistically portrayed despite the science fiction nature of the book.
3) The author makes it seem like the only way Katie can escape her disease and do normal things is to die.
4) I'm kind of sick of the "sick girl" trope playing around YA right now anyway. I read this because my students love it.
5) Charlie is boring. He had potential to be interesting, but there's no internal conflict with him about Katie's disease or anything beyond a bit of self pity about swimming.
6) Charlie's parents' conversation at the car door was awkward, not sweet.
7) Pacing is so off in this novel.
8) Zoe's character. Girl can hold a grudge over nothing for a decade.
9) Lack of description of what were supposed to be profound moments; see concert and studio.
10) Everything (else) plays out perfectly in the end and everyone grows because of this experience. the author pushed way too hard to make something meaningful come of the ending, and life is just way more messy than that.

Now, my students will love this, because apparently they love to torture themselves and their teacher with average-at-best writing. I'll booktalk it because all my girls won't be able to get their hands on it fast enough. Junior high, man.