You went to Kimetsu Academy,and you were doing pe in teams, Zenitsu was in a team with Tanjiro and Inosuke, and you overheard him talking to the others

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!"