Hi Tabitha. I did not find evidence of who Martha Walden's parents were. She may have been related to John Chavis Walden who also lived in Chatham County but was not one of his children--perhaps a cousin, niece or more distant relative?
I guessed her birth year at about 1762 since her son James was born about 1783. There was another Martha Walden born about that time, but she remained in Dinwiddie County.
Based on the information we have now, I guessed your Martha might have been the daughter of Elizabeth Walden who left Surry County, Virginia, about 1746 when the court charged her with living in adultery with James Evans and bound out her daughter Mary.
Paul