It's been a long time since I've written a review, but I'm going to give this a try. There's going to be a vague spoiler about the general type of ending (because it's all I could think about), but nothing too terribly specific.
This book is a lovely character study--or rather two character studies--of a pair of young women, both high school soccer players, who develop a long-distance friendship and, eventually, romantic feelings for one another. Don't read it. At least not until the next book in the series comes out. You'll want the next book as soon as possible because the relationship is completely broken at the end of the first. Given what both characters go through, given what they mean to one another, seeing it end on a break felt gutting. As I was reading and watching the Kindle progress tick up through the percentages--70%, 80%, 85%--I kept thinking, "No...no...no! There's not enough time to fix this!" And there wasn't. So there's that.
Now, all of that said, this is a very well-written book. The lead characters are both fully developed and relatable, their difficulties are understandable and engaging, their friendship feels utterly natural (and speaking as someone with a long-distance friend, very familiar), the supporting characters had enough detail to make them interesting, and it's difficult to see how the book could've ended any way other than the way it did, given the respective ages of the main characters and the challenges they faced. The book has a lot to recommend it, and I'm absolutely going to read the next book in the series. But I wish I'd followed my own long-distance friend's example and read the ending of this one first; I still would've read the book, just at a later date.
So, I rate this one at 4.5 stars, rounded down because it made me sad. I do highly recommend it, but I'll leave the timing of that reading up to you.
(ETA: Book 2 is out, so grab both of them and you're all set! My previous "don't read this yet" suggestion is hereby rescinded.)