Takamiya Chinatsu from 教育指導 Kyouiku Shidou BISHOP visual novel

A straightforward and energetic girl who is part of the track club.
Due to her child-like face and innocent personality, she is considered the mascot of the track team. She has a lot of friends even outside her club.
In contrast to her small frame, she has large tits.

She loves running and is not interested in making record, but she wants to run fast and is unhappy with her breasts growing bigger. Because of her childish personality, she is interested in the protagonist, one of few males on campus, and innocently interacts with him.

She has next to no knowledge of sexuality and has never masturbated before. And is easily tricked by the protagonist due to her naive nature.