She lit up as she descended the stairs to the hall, knowing that she would not have dared had her father been at home. He had precise ideas about where a woman should be seen smoking: not in the street, or any public place, not on entering a room, not standing up, and only when offered, never from her own supply - notions as self evident to him as natural justice. Three years among the sophisticates of Girton had not provided her with courage to confront him.
The protagonist feels a sense of liberation as she walks down the stairs, realizing she wouldn’t have done so if her father were present. Her father has strict views on propriety for women, especially regarding smoking. He believes that a woman should only smoke in certain private contexts and only when invited, emphasizing a strict code of behavior that she finds oppressive. These views are so ingrained in him that he sees them as unquestionable truths.
Despite her time at Girton, where she was exposed to a more sophisticated and liberal environment, she still lacks the confidence to challenge her father's outdated beliefs. The conflict between her desire for independence and her father's controlling nature creates a tension that reflects broader themes of societal expectations and personal freedom. She finds herself torn between the influences of her upbringing and her experiences at university.