Supposing SG to have been at least eighteen at her first, very awkward appearance on stage, she must have been born some time before 1745.
SG wrote a poem entitled "On the American
Disturbance . . . To the King
", which she preserved in her manuscript album: the earliest dated among her writings.
SG is last heard of in 1795; her manuscript hoard includes a commercial account book which runs until 1813. She was alive at the first and perhaps at the second of these dates, possibly at Colyton
, where her manuscripts were discovered a century and a half later.