I bought “Misty of Chincoteague” for my Daughter when she was 7. We have also seen the movie. Both the book and movie are excellent children’s stories and not bad for adults either.
My wife and daughter are horse-crazy, so we went to Chincoteague Island when we were in the neighborhood a few years back. Clearly the ponies were the top draw to the island, but it was amusing to see how the NPS tried to de-emphasize them and point us toward the foliage and native animals.
I “grew up” with my daughter with those stories.
Then we got horses and it all turned to manure (LOL!).