Yay, this one has a picture of the cover! Like I said about If Wishes Were Horses, I read this book a bunch of times. Although in this book, the twins got better at riding from riding without stirrups, and that IS hard to learn. I can't believe there are two other books in this series, though! Maybe I'd heard of them but could never find them.
Nancy Wright Grossman puts a great spin on the importance of being yourself in this horse story for pre-teens. Meg and Morgan are identical twins. They look alike, think alike and even like the same things... more at http://equus-blog.com/the-judge-is-se...