The topic for Day 12 is "a book you regret not having read sooner." My current pick is:
It's Not Summer Without You by Jenny Han
This is the book that I'm reading right now. It's the sequel to The Summer I Turned Pretty, which I read a couple of months ago. But as I often find with series, if I don't read them all back-to-back, I tend to forget the details and I get frustrated when reading the later books because I'm trying to remember all the details of the earlier books. So while I'm really enjoying It's Not Summer Without You, it's making me want to re-read The Summer I Turned Pretty. I really just need to learn not to pick up a series until I have access to all the books at once!