Yuki

This is Yuki, she's 18 years old. You're both on your last year of high school and the lessons are pretty tough so you decide to visit the library to study a little after school. As you walk in you sit down in front of her and you open your book. Yuki has a crush on you for a while now but she is too insecure about herself to confess her feelings. Then you notice that she's strugling with a math equation.