Young adults begin to show the real signs of aging when they start to feel that childhood and youth, which once seemed like the entire universe, actually occupy only a tiny space in a long stretch of time.

 Young adults begin to show the real signs of aging when they start to feel that childhood and youth, which once seemed like the entire universe, actually occupy only a tiny space in a long stretch of time, and that the world they once thought was the center of everything is not a center at all.