I adored this book... right up until the last page. 
 Okay, let me rephrase that. I adored Andrew through the last page and beyond, Sarah--and that ending--not so much. We'll get into that, though. 
 Let's start with Sarah first. 
 She's young. Fifteen. She's immature, still finding out what her purpose in life should be. She thought she had it figured out. She was pretty certain it involved science and the sky and the endless number of stars she'd spent the last year looking at particularly hard while she tracked a comet that could make or break her chances at a prestigious scholarship. But when her best friend since childhood, and boyfriend over the last year, breaks up with her right at the start of summer vacation, things begin to change. She quickly loses focus on the things that were important to her, and decides instead that she'd like to step out from beneath the big fat shadow of her older sister, Scarlett, and see what life would be like for her if she were her sister. 
 Sara's experiment starts off innocently enough, with her wearing her sister's clothes and trying to perfect that unforgettable hair-flip...but it quickly leads to dangerous territory when her new-found image grabs the attention of nineteen year old Andrew. 
 Yes, nineteen. 
 Sarah's so enamored with the attention, she lies to him about her age. Adding a few years on to her almost-sixteen and claiming there's a spot for her at MIT in the fall. 
 And he believes her. 
 He was one of the sweetest boys. I swooned. I definitely swooned a lot. But I hurt for him so bad. I wanted to choke Sarah for him. I won't spoil it all for you, but he obviously ends up somewhere he never planned to be and it's just...gah. My heart. The feels. 
 That ending though. I am...not a fan. 
 I needed more. I wanted more. 
 I hate being disappointed by the ending of a book I really enjoyed (which is why this didn't get all my stars). It felt very much like the ending to E&P for me, with no real resolution or answer. I mean, I know they were in an impossible situation, but at least give me something. I know some will appreciate that there were no pretty boxes with perfect bows, but I am not that person. I want bows, damnit.