In "My Older Sister Looks Younger Than Me, And I Know Why," the narrator grapples with the striking contrast between their appearances, despite being siblings. While others often mistake them for the same age, the narrator realizes that their sister’s youthful glow comes from her carefree spirit and a passion for life. As they delve into the reasons behind this phenomenon—lifestyle choices, self-care routines, and positive energy—the narrator gains a deeper appreciation for their sister's influence, learning that true youthfulness stems from more than just age; it’s about attitude and joy.