Yes! You may pay your loan in full through the GLoan feature in the app. You can check the total amount that you need to pay through your amortization schedule or by simply multiplying your monthly due amount to your remaining months to pay the loan.
Paying early boosts your chances of getting a better GScore -- the better your GScore, the more you can borrow at better terms. If you want to know more bout GScore please visit What is a GScore?