Meet Felicity by Valerie Tripp, 1991.

This is the first book in the Felicity, An American Girl series.

Felicity, or Lissie as her family sometimes call her, is the daughter of a prominent store owner in Williamsburg, Virginia in 1774.  Sometimes, her father allows her to help in the shop, which is something that she enjoys.  However, that has happened less since her father took on a new apprentice named Ben Davidson.  Ben is fairly quiet and shy, and Felicity is only just getting to know him.  She sometimes envies boys for the more exciting opportunities they have while she has to help with more routine chores, like sewing, at home.

One thing that Felicity loves more than anything else is horses.  One day, she goes with Ben while he makes a delivery to Jiggy Nye, the tanner.  Jiggy Nye has a new horse that he says he won at gambling.  However, Jiggy Nye is cruel to any animal he gets, and Felicity fears for the beautiful horse he now has.  When Felicity tries to see the horse, which she calls Penny because of the color of its coat, Jiggy Nye drives her away.

That the horse is a fine animal and that Jiggy Nye is treating it badly are obvious, but at first, there doesn’t seem to be anything that Felicity can do about it.  Then, Jiggy Nye shouts at the horse one day that it’s worthless because he can’t handle it and that he’d give it to anyone who can ride it.  Taking Jiggy Nye at his word, Felicity sets out to tame Penny.

Every morning for about a month, Felicity sneaks out of the house early, dressed in a pair of breeches that she borrowed from Ben without his permission.  She goes to visit Penny and gradually gains her trust.  When Penny finally allows her to ride her, Felicity thinks that she has won ownership of her, but Jiggy Nye accuses her of theft and takes back the horse.  He denies that he ever promised to give her to anyone who could ride her, although Felicity’s younger siblings agree that they heard him say so.

Felicity fears more than ever that Jiggy Nye will kill Penny, but now that she no longer has a chance of getting her from Jiggy Nye for herself, can she find another way to give Penny her freedom?

There is a section in the back of the book that describes life in Colonial America, particularly in Williamsburg, Virginia.  It also mentions the Colonial Williamsburg living history museum.  Another book about life in Colonial Williamsburg, with photographs from the living history museum, is Mary Geddy’s Day.

This book is currently available online through Internet Archive.