When Starlight agreed to move to Ponyville, she thought it would just be magic and all that. She probably should have realized she would have to make friends, given Twilight's title of Princess of Friendship and all. She had trouble making friends until she meets a showmare in the spa. The two hit it off and Starlight confuses herself when she gets angrily defensive of the mare and her feelings she's never felt for anypony before.

(https://www.fimfiction.net/group/217012/sunsets-and-the-others-lives)