Where I live the shower after PE is not obligatory. Everyone does it according to their own wishes and principles. I respect each choice and understand both. If I have sweated a lot and I still have classes afterwards, I prefer to take a shower.
No I'm not gay, and I don't feel comfortable because I want to be friends with this person without thinking that they might want more. I don't know why, but I don't feel the same way with a boy. Maybe because of the opposite sex. Sorry, it's not easy to express this kind of emotion in words (especially in English).