Do you have to enroll at a college first before can apply for financial aid?

No, you generally don't have to be enrolled at a college to apply for financial aid. In fact, the application process usually happens *before* you enroll. You apply for financial aid (like the FAFSA in the US) to determine your eligibility *before* you're accepted and choose a college. The aid you're awarded is then used to pay for your college education once you've been accepted and enrolled.