How do I input prepaid state tax that I made in 2020 for the year 2021?

In December 2020 I prepaid CA income tax for the year 2021. Can anyone advise how to input this into TurboTax? When I try to input the prepay date of 12/2020, TurboTax tells me that I can't list a prepay date prior to 1/1/21. Thanks in advance!