Simplify the following text for a Grade 9 native English-speaking person.
Original: Her recording career began in 1949 at the age of twelve , when she changed her stage-name to Hibari Misora ; which means `` beautiful skylark '' and starred in the film Nodojiman-ky Ã jidai .
Simplified: Her recording career began in 1949 at the age of twelve , when she changed her stage-name to Hibari Misora and starred in the film Nodojiman-ky Ã jidai .