SOLVED. Horses riding lessons children's/Ya book [s]

[Weirdredstreak]

So, this book's authors last name starts with the letter M. I read it about 8 years ago from a library, then it wasn't a new book. From what I remember there were two daughters and one started riding lessons at a riding school, then the other sister was feeling jealous and convinced the parents to let her go to although she was having art lessons? The sister that had been riding for a while managed to convince her sister to choose to ride this horse skylark? Who was really flighty, while she rode one of the gentlest horses except I think they were made to swap at least the sister that just started riding didn't end up riding skylark?. There was some kind horse show and the sister that had been riding the longest ended up riding skylark? Because the other really quiet horse had too many people riding it.

[M—]

Ann M. Martin wrote Me and Katie (the Pest) about two competing sisters who take up horse lessons. It was a plot point that the older sister wanted to start riding lessons as a way to excel in something the younger sister didn't already excel in naturally, and the younger sister got jealous and insisted on riding lessons too.

[Weirdredstreak]

Yes that is it thank you!

[M—]

Excellent!