Passage: James Byron Dean was born on February 8, 1931, at the Seven Gables apartment on the corner of 4th Street and McClure Street in Marion, Indiana, the only child of Mildred Marie (Wilson) and Winton Dean. He was primarily of English descent, with smaller amounts of German, Irish, Scottish, and Welsh ancestry. He also claimed that his father was partly Native American, and that his mother belonged to a "line of original settlers that could be traced back to the Mayflower". Six years after his father had left farming to become a dental technician, Dean moved with his family to Santa Monica, California. He was enrolled at Brentwood Public School in the Brentwood neighborhood of Los Angeles, California, but transferred soon afterward to the McKinley Elementary School. The family spent several years there, and by all accounts, Dean was very close to his mother. According to Michael DeAngelis, she was "the only person capable of understanding him". In 1938, she was suddenly struck with acute stomach pain and  quickly began to lose weight. She died of uterine cancer when Dean was nine years old. Unable to care for his son, Dean's father sent him to live with his aunt and uncle, Ortense and Marcus Winslow, on their farm in Fairmount, Indiana, where he was raised in their Quaker household. Dean's father served in World War II and later remarried.

Question: How old was Dean when his mother died?
nine