Who is Granny from Confessions of a Failed Southern Lady and what is their importance?

Granny, Lura Ruding nee Upton, is Florence's grandmother, who lives with Florence and her parents. Since Granny's attempts to raise Mama as a Southern lady fail, she is eager for a second chance to rear a lady when Florence is born about a year after Mama marries Herb, so she moves in with them. Granny attempts to train Florence to become a lady while Herb educates her. Florence is promoted to Kindergarten A because she is too advanced for Kindergarten B which worries Granny because ladies should not be too bright. Granny and Jensy force Florence to accompany them on their temporal acts of mercy, visiting the sick and such.