To repeat what was noted above, we didn't find Lexile scores to be very useful. My DD12 was supposed to be reading Don Quixote at 9, which was silly. We found a few lists of high Lexile books with age-appropriate material, but most of them just weren't very good.
Instead, we decided to focus on using high quality writing to instill a passion for reading. I'd rather she become immersed in a well written story than read big words and get bored. Google Amazon Newbury award - you can search award-winning children's books by age, subject, etc. We looked a few years older than she was, but didn't get carried away. The age goes up to 12, so this is a great source for our kids up to age 8-10.
It seems to have been successful - at 12 she's raiding my shelf for my old HS books - Animal Farm, Lord of the Flies, etc - and older sister's Chaucer has piqued her interest.
