Are there any teachers you would feel comfy talking to at school? Eventually talking is always better than hiding but it is really hard and has consequences. Different schools have different policies but it is possible that the school would contact your parents or make certain members of staff aware. If you want to limit the number of people that know then it would be a good idea to work out who the safeguarding lead is for the school because it will be their choice and they would always be told.
I chose to talk to a teacher about stuff and as far as I know she kept it very quiet, at the time that is exactly what I wanted...but I regret now that it was a wasted opportunity to access some pro support. I would have hated the idea, but maybe things would be better now.
If you just want to hide it - what do Islamic girls wear for pe at your school? Would you be able to wear the same? Schools cant force you to wear short sleeves and that would fit the dress code.
