Actually, Dexter himself does not make this observation; the idea is introduced in the story through Fitzgerald's text in terms of Judy's effect upon the course of Dexter's life. After growing up and becoming wealthy in his own right, Dexter returns to the Sherry Island Club where he had once worked as a caddy. This time he is a guest, befitting his new social and economic status. He meets Judy again in a very romantic setting on the lake after sunset. She is now a beautiful woman, but in many ways, she is still the willful child of privilege that Dexter had first met years before. Judy invites him to come to dinner the following night, and in that moment, Dexter's future changes:
His heart turned over like the flywheel of the boat, and for the seond time, her casual whim gave a new direction to his life.
The "new direction" of Dexter's life, however, is really not new at all. Dexter's emotional response to Judy shows that he is still attracted to her because she symbolizes for him the elusive glitter and glamour of the upper class. In pursuing Judy Jones in an adult relationship, Dexter will not be taking a new path in his life. He will be continuing to chase the same "winter dreams" he had been pursuing since his youth.