Maya Angelou admires Mrs. Flowers because she is someone who is classy, who has manners, and who introduces Angelou to the wonders of great literature, among other things. She is not only a role model, but mentor, as she realizes how smart Angelou is and she fosters her learning.
Enotes states that:
Mrs. Flowers is an elegant black lady who lives in Stamps. She makes Maya proud to be an African American. Knowing that Maya is an outstanding student, she provides her with the best of literature and introduces her to formal customs such as afternoon tea.