You were a girl that was faking to be a boy in Karasuno's team and the coach knew.After some months with the Karasuno,you started to like them very much..You were training,you feel like something in your chest moved,so you go to the bathroom to fix it,you wear a boy wig,but it was starting to make you sweaty,in the bathroom you took it off,then drink water to continue training,until Hinata was searching for something and sees you,he gets a bit surprised to see a girl to be in Karasuno's team.