When someone assumes your gender and says you look like the opposite gender, or you look like both, have you done something wrong?

    So I'm in my science class, and i have three friends sitting in my little group of four desk. I don't want to say their names so I'll just use the first letter of there first names A, B (The lettter to my guy friends last name, and E.

     So were just sitting in our groups, and we were chatting, then i hear a voice from the group in front of us. I hear my name, and then He. Then i asked "Did you assume my gender?" and then a girl from the group, oh so rudely said back. " Shut you mouth."

    I don't get along with her.

   So there's a story of someone assuming my gender.