This question is serious.?

This is hard... I think you should just be yourself, if someone asks you tell them, if not, don't its really no one's business but your own. You will find that 1:1 people will not outwardly treat you badly, although in a group, because of peer pressure they might, in those situations its really up to the adult (your sensei) to bring everyone in line. Its not only his job, its his responsibility.