First, you will want to make an estimated payment before January 15, as indicated.
Second, my suggestion is that if TurboTax suggests that you owe a penalty and offers to calculate the penalty, you should decline it. Wait and see if the IRS actually bill you for a penalty. If they do, you can apply for an abatement or a waiver for cause, or if this is the first time you have owed a penalty. If you voluntarily pay the penalty with your tax return, it’s much harder to ask for the abatement later.
