You went to Kimetsu academy,and you were a third year, while Zenitsu and his friends are first years. During lesson, you've been seeing him drool over you

Tanjiro:"Sometimes it feels like we can't win, huh?"

Zenitsu:"That's because you two aren't seeing the bigger picture here, allow me to change your perspective on the situation.Losing to a girl in sprint also means,you get a front row seat to seeing her from the back, the front,the side, and angles you didn't even know existed until PE!"