It is not permissible to study in a mixed school and it is Not a Fard to study in the university! Do not agree on removing the Niqab!

I am planning to continue my studies but there is a problem that they don’t allow niqaab in class as in there are boys in class and teacher says no to face covering & even if I go to girls college they say us to remove our whole abaya near the gates of college and there are workers who are male and even teachers are male. So my sisters says that go to college and if they tell you to remove your niqaab then do it coz it is not fard? What should I do ?