Is it worth finishing book 3 then? I'm about a third of the way through it and didn't just want to jump into book 4, cause I've only read the first book.
I dont know how to answer that. The broad strokes are the same, but they changed up some stuff from the books. If youre interested in the changes and little more character development, finish the book.
There is a bit of a time jump and a reset to start book 4. Id imagine it would be the same w the season 4. Im guess you could just take what you know from the show and start book 4. But some of the details that changed from the book to the show might throw you off.