@karolyn
I don't think it's a guy, even tho the translation used a he to describe she I'm pretty sure she is a....she. The swimsuit and the fact that she is competing for a spot in the woman's competition makes it quite clear that she is a girl even if she looks androgenous
Have to agree with @kashell11 What culture puts a co-ed bathroom in a high-school? If she was a boy, she'd definitely be freaking out about him also being in a girls bathroom.