Midnight Magic: The Wizards of Equasia

This is a story that I started when I was ten years old and am rewriting, again. The first two books really are an introduction, the third is a lead up to the fourth, and then the REAL action happens. Still, I hope you like it and I would love feedback.
Sarah Orenda has lived as a street urchin most of her life, with hardly any knowledge of her parents. So when she stumbles across talking animals and a magic mirror, her whole life changes. She ends up in an incredible world of magic, horses of unusual colors and patters, new friends, and intriguing magical lands. She meets a colt named Midnight who becomes her lifelong friend, almost like her equine brother. But in the midst of it all is a dark force that seeks to destroy Equasia, and Sarah and Midnight are the only ones who can stop it.