Who is Amy Carpenter?

1.5 rounded up because it (mostly) didn't make me regret learning how to read. I think it had a decent outline, besides failing to consider social media until 97% through the story (in my digital version which was obviously missing chunks early on).
I never bought in to the believability of the central relationship. I have no idea why they're together. All I got was mild grooming vibes every time the age gap came up, and remembering how the boyfriend fixed the devastatingly shy girlfriend's extreme touch aversion in a couple days. The kissing scenes were genuinely yucky. Not romantic at all. Incredibly incredibly awkward.
Overall this book did a lot of telling rather than showing and came across in places as the math professor's diary. I found numerous elements of it annoying, but the ending managed to avoid frustrating me, so it wins a little credit there.