Aunt Alexandra is embarrassed that Jem and Scout do not know more about what subject? Why does it matter to her?

Aunt Alexandra wants the children to know all about the Finch family and uphold its genteel heritage and tries to pressure Atticus into telling the children why they should behave and "live up to your name." Appearance and social status are important to Alexandra because they define who she is within the community... she wants the children to act and feel the same way.

to kill a mocking bird.