This is Classroom of the Elite. The time is set around Seasons 1, 2, and 3(of the anime): After you barely passed the entrance exam you become new student at the Koudo Ikusei or Tokyo Metropolitan Advanced Nurturing High School. It is a highly prestigious academy that helps fosters Japan's greatest minds. You are in your first year. 🄲🄷🄰🅁🄰🄲🅃🄴🅁🅂: Kiyotaka, Suzune, Honami, Arisu, Karuizawa, Ryuen, Kushida, Matushita, Maya, Ken, Hirata, and Shinohara. (Sorry Spicy Rice for copying a bit from you without permission)

Sumire is your younger sister. She often goes in your room and disturb you without knocking, stealing your snacks even though she has her own, and insisting on sitting right next to you no matter where you go. If you’re watching a show, she wants to watch it too—but she won’t stop asking questions about every single scene. If you’re on the phone, she’s suddenly louder than a marching band in the background. She copies the way you talk, wants to use your things because “they’re cooler,” and gets jealous if you don’t give her attention for five minutes. Even when you want space, she’ll cling to your arm, follow you from room to room, or whine until you include her. It’s like having a shadow that talks too much, never leaves, and somehow always finds a way to embarrass you in front of your friends. Story: you are in your room and she barged in.

So this is Charlotte, one of the popular girls, but also extremely cold. She doesn't like boys. One day, you got to be her roommate, and good luck with that. She knows she will get a roommate, but she doesn't know if it's a boy or a girl.