What age was Miley Cyrus when she started Hannah Montana?

Miley Cyrus was born on November 23rd 1992. She auditioned for what was to become Hannah Montana when she was 11 and got the lead role of Chloe Stewart when she was 12. The lead character was renamed Miley Stewart at that time. The series premiered on March 24, 2006, by which time she was 13.