This is an early reader horse story from the Breyer Stablemates series.  Diamond is an older horse who is purchased by a stable for lessons.  Ava is the only girl who realizes the value of Diamond’s experience, everyone else favoring youth.  When Diamond and Ava win a competition, the crowd goes wild and the reader gets a sense that Diamond has earned her place in the stable.  These are good little stories and the values and lessons learned are positive.