Olive, check out your local library. They often have small starter readers to borrow that will give you an idea of the kind of books your DD will find at her level and interesting.

Lots of the toddler board books we had at home were a good starting point for DD. The reader series from preschool and school are hard to find! I know Grug and the Little Miss/Mr books DD liked/likes, but it took her a while to read those.