All perfect praise be to Allah, The Lord of the Worlds. I testify that there is none worthy of worship except Allah, and that Muhammad is His slave and Messenger.
Borrowing money with interest is forbidden Riba (interest and/or usury). However, if a student borrows money with Riba in order to study, then this does not make it forbidden for him to benefit from his certificate and this does not make his job or whatever he earns from it forbidden as long as his field of work is permissible.
This is because the sin in an interest-based loan is connected to the person dealing in it and not the money itself (or whatever it is spent on).
If someone has borrowed money with Riba out of ignorance of its prohibition, then we hope that he is not sinful and it is not necessary to leave school since he has already borrowed the money and he is required to repay the loan.
Allah knows best.