Can I pay the first time homebuyers credit in advance? I just sold my home in 2017 and made a profit and would like to pay now instead of waiting until 2017 tax return.

Yes, you can repay more than the minimum repayment required.  Follow these steps:

Sign into your account and click "Take me to my return"

In the Search box (upper right of program) search Homebuyer credit and click the "Jump to" link from results

TurboTax will guide you through a series of questions and you will come to a page that says "If you like, you can pay more than the minimum."  Check the box for "We would like to repay more than the minimum amount due." and enter the amount you would like to repay. (click on screenshot below for detail)

NOTE:  Here is a link to the IRS to look up your outstanding balance:   https://www.irs.gov/individuals/first-time-homebuyer-credit-account-look-up

After you file your tax return, wait about 3 months and recheck the outstanding balance to ensure the payment was properly applied to your account.