Yes, Memoirs of a Geisha is a memoir. Only, because she is remembering a time in her life that was important to her.
Her name is Saiyuri.
I think it is a PG.
Memoirs of a Geisha is the novel by Arthur Golden, published in 1997
In my opinion, Mameha was Sayuri's savior. She guided her to escape from a life of constantly being stood on by Hatsumomo. Although, it's revealed in the end that it was the Chairman who had asked...