When Luce did look in the mirror, she thought she might still be sort of pretty, if you went by what most people thought was pretty. And if that's the way you went, you had your own problems. It wasn't like being pretty was an accomplishment, and it would go away in time. So it would be a mistake to get too hung up on it.
Luce reflects on her appearance, considering that she might still fit the conventional definition of beauty that many people adhere to. She understands that this view of herself is shallow, as she realizes that beauty is not an achievement and is temporary. It serves as a reminder that attaching too much importance to physical attractiveness can lead to problems, as it is fleeting and not a true reflection of one's worth.
This insight reveals Luce's deeper understanding of self-worth, suggesting that valuing oneself based on outer appearances is misguided. She acknowledges the societal pressures surrounding beauty but chooses to maintain a more profound perspective on her identity, indicating a desire to look beyond superficial qualities. This complexity of thought showcases her character's growth and introspection amid the standards imposed by society.