Final answer:
In the novel The Great Gatsby, James Gatz changes his name to Gatsby at the age of 17.
Step-by-step explanation:
In F. Scott Fitzgerald's novel The Great Gatsby, the central character, James Gatz, changes his name to Jay Gatsby when he was 17 years old. Gatsby is a self-made millionaire who reinvents himself and creates a new identity in pursuit of his American Dream.