Conversation so far:
Where was Christina Aguilera born?
Christina María Aguilera was born in Staten Island, New York City, on December 18, 1980
How long did Christina Aguilera live in NYC?
Christina Aguilera's family moved frequently because of her father's military service, and lived in places including New Jersey, Texas, New York, and Japan.

Question: When did she begin singing?
Self-contained rewrite: When did Christina Aguilera begin singing?