If you like stories surrounding horses, strong characters and a good story line, you've found the right series and author... though this is book 3 and you might want to begin with The Project horse which is book one in the Ocala Horse Girls series!
The author, Natalie Keller Reinert has written multiple stand alone earlier series that are amazing reads and in her Briar Hill Farm and Ocala Horse Girls Series the characters interact. As I have read all the books in every series, it is like having old friends visit.
In the Regift Horse Evie is living in a comfortable rut, living in her own trailer, working with the horses at her friend's racing barn and looking out her window at her beloved Eventing horse, who has become a friend and lawn ornament due to a permanent injury. Though she is content with her life, with the injury of her horse she has given up her dream of becoming a top level Eventing rider - until she gets an incredible Christmas top level (re)gift horse from her cousin. The only catch is that she has to train with a notoriously negative, yet gorgeous trainer. She upends her life to go for her dreams and the reader gets to find out whether she will soar, or flop in her attempt to become a top level rider.