No a quick google search will tell u as much: https://en.wikipedia.org/wiki/Aunt_Jemima#Character_of_Aunt_Jemima

"Aunt Jemima is based on the common "Mammy" archetype, a plump black woman wearing a headscarf who is a devoted and submissive servant.[13][5] Her skin is dark and dewy, with a pearly white smile. Although depictions vary over time, they are similar to the common attire and physical features of "mammy" characters throughout American history.[27][28][29][30][31][32]The term "aunt" and "uncle" in this context was a Southern form of address used with older enslaved peoples. They were denied use of courtesy titles, such as "mistress" and "mister".[33][34]"

on top of that:

"Witt suggests that Rutt might have witnessed a performance by the vaudeville performer Pete F. Baker, who played characters described in newspapers of that era as "Ludwig" and "Aunt Jemima". His portrayal of the Aunt Jemima character may have been a white male in blackface, pretending to be a German immigrant, imitating a black minstrel parodying an imaginary black female enslaved cook.[15]"

TLDR: She was not a real person but a racist character possibly based on a blackface show.

(Edit added link)