I've read all three books and loved them. Highly recommended!

The books are in no way boring or slow-paced. A lot happens in book 1. But if we look at it as getting from A to B, B is just "we got to know the characters and a friend group formed." Book 2 is El's senior year. The graduation is inevitable on the calendar. But you would never be able to guess how much of an impact El will have on the school! (Avoid reading the title of the book if you don't want spoilers.)

Book 1 was quite PG-13. It had like one stabbing and the ever-present mass death of children. And one kiss. Book 2 goes a bit further.