refinance - date of purchase

We purchased our home in 2003, refinanced with a new lender in 2009, and refinanced with another new lender in March 2021. The loan was then sold twice. So, we've got four 1098s for our property for this tax year (original refinance lender + 3 companies that we paid mortgages to during the year). Question is: For each form, TurboTax asks when was the home purchased. is the answer to this question (a) 2003, when the house was initially purchased? Or (b) For the initial refinance, indicate 2009, for the second refinance indicate 2021?

Or... is the answer "it doesn't really matter," since it appears TurboTax is saying we're better off with the standard deduction anyway?