That is about when people started to use surnames. So maybe you will have to stop here. In a tradition there is often a grain of truth. Of course, it is unlikely that your ancestor served under Washington. He was likely a private who never saw Washington.
Genealogy is an admirable hobby or profession.
I have learned a lot of history and geography. In fact local history and families are closely connected. I have met many nice people. We have helped each other. Genealogical research adds to the permanent record of our country.