One theme that conveys itself, in part, through setting is the theme of deprivation. The historical time period here is the Great Depression and the years of WWII. The Depression is a time of great deprivation. The mother who is narrating her version of the story tells of poverty, the need to work outside the home, and the need to take her daughter to a child care provider that she hated. This is a reflection of the social and economic situation of the time. As a single mom, she had no choice.
But those choices had the effect of deprivation on her daughter. She is neglected in school and at home. The daughter was rather easily overlooked once the mom remarried and other children entered the picture. The daughter was deprived of an easy, young childhood due to the responsibilities of her busy mother. This deprivation manifests inself in the daughter's lack of self-esteem and confidence, which only comes out at the end of the story when she discovers a talent for comedy.
Sorry, but can you explain what deprivation is?