Because girls were not allowed to go to school. They were expected to help with household chores, such as dishes, laundry, cleaning the house, babysitting, etc. They were expected to help their mothers, not to get education. Some people did read on their own or get knowledge from their family members. A lot of the families had the mother teach their daughter some basic things.
Girls were usually seen as help in the home and taking care of the kids. The women that did go to school would learn about home economics such as sewing, cooking, and learning to use new domestic inventions.
