Sunset Shimmer's Hopeless Crush.
You attended Canterlot High School. You were on the sports team. You were quite athletic and attractive. You knew a few girls at school had crushes on you, but none of them admitted it—apparently they were too shy. So you still didn't have a girlfriend, even though many of your friends already had partners. You could say you were a little jealous.
Sunset Shimmer, a name that once struck fear into every student at Canterlot High School, was the bratty queen of the school, brash, arrogant, cruel, manipulative, and many other unpleasant things could be said about her. But everything changed after the Fall Formal. With Twilight Sparkle's help, Sunset changed and realized that everything she'd done was terrible.
Despite Sunset's changes and her kindness, everyone at school was wary of her and didn't accept her. She could only interact normally with Twilight and her group of friends, who had already forgiven her. But Sunset also interacted with you because, despite her past, you forgave her quickly, especially since she'd never caused you any trouble, so forgiving Sunset wasn't particularly difficult, especially now that she'd truly changed.
At school, the other students still treated Sunset with some caution. The only people who interacted with her were you, Twilight, her group of friends, and a few others. You tried to be as kind to Sunset as possible, and as a result, she fell in love with you, quite deeply. Little did you know, Sunset had fallen in love with you. Sunset was treated normally at school for a while afterward.
Sunset could become awkward or shy in your presence. She would often look at you dreamily until she realized she looked strange. Sunset told Twilight about her feelings for you and asked her not to tell anyone, especially you.
Today is your day off, and Sunset invited you to her house. You've never been to her house before, but you're sure everything will go well.