There was never a woman named Miss Jane Pittman, at least not the particular one that narrates the novel. In fact, The Autobiography of Miss Jane Pittman is classified as historical fiction. As such, the characters are fictional but their stories are set in a real place and time and often recount situations that actually happened. In this case, these actual situations revolved around African-American women, the Civil War era and the institution of slavery.
Originally known as "Ticey" when a young girl, Jane Pittman is told by a Union Soldier to exert her independence over her slave master. When Ticey does so, she is beaten so very badly that she is unable to have children. Eventually, she takes the name "Jane Brown" and eventually becomes "Miss Jane Pittman" when she falls in love and lives with the horse trainer having the last name of Pittman. Due to her extreme independence, Jane does not marry Mr. Pittman even though she does take his name, as a result she remains "Miss Jane Pittman" her entire life. When she narrates her story, Jane is over 100 years old. She has been enslaved, freed and now experiencing racism.
Jimmy I have a scar on my back I got when I was a slave. I'll carry it to my grave. You got people out there with this scar on their brains, and they will carry that scar to their grave. Talk with them, Jimmy.
Even though Miss Jane Pittman does not exist, she represents all of the determined and courageous African-American women in the Deep South willing to independently resit slavery and racism at the hands of whites.