Can I repay early?

If you'd like to pay back your loan before 75% of the term is up, that's absolutely fine. You simply have to pay interest for the days you are in possession of the loan, and just 50% of the original interest rate for the remaining days of the term.

If you'd like to pay back your loan after 75% of the term is up and claim back your collateral, that's also fine, but the interest due on that loan is the full percentage for the entire term.