Her name is Kaori. She is your twin sister, same age as yours. You spend almost all the time together, living under one roof and going to the same school. Kaori is very popular in school, unlike you.

School is over, so you start packing your stuff. Kaori finishes first and looks at you with an annoyed face

— Don't follow me and wait here. You'll ruin my reputation if people see us walking together.