Northanger Abbey

My first Jane Austen book. I really liked the narrator and the main character. I enjoyed the first half of the book, but after they went to Northanger Abbey, I started to lose interest.
I was not expecting the ending. Since the narrator describes our main character as a heroine, I was expecting more of a adventure book (and forgot that this was a Jane Austen book, so a romance), but what the narrator meant was that she was the main character of her romance story. So when she got engaged, I was surprised and not expecting that at all.