You are correct. On February 9th, 2018, Congress retroactively extended this through 2017.
It will likely take several weeks for the IRS and TurboTax to get the Forms ready for that, so you may want to wait to file your tax return. The other alternative is to file now without it, then amend your tax return later to add the credit.
You can keep checking back in your return to see when it's available.
