why wont turbo tax let me put in my payment date may 17 2021

Please be patient.  Since the change to the filing date and the payment date was only announced on March 20, it takes awhile to get the software updated across the desktop and online editions for the personal, professional and business programs. 

Then TurboTax has to wait until the IRS has changed their systems to accept payment dates after April 15, 2020 and on or before July 15, 2020 for a 2019 tax return, otherwise the tax return would be rejected by the IRS. 

This date change affects all tax preparation software companies and paid tax professionals who provide e-filing for their clients.