what do i do if im unable to pray due to being at school?

I'm a student who lives in america, my school is mostly christian and we don't have very many Muslim student's i'm afraid it would be unacceptable to pray at school due to the setting being not very clean and staff not allowing me, does this mean I have to make up my prayers after school? Is that acceptable? I'm sorry if this sounds like a silly question I am just starting to learn prayer this year. Thank you.