Complex sentence: Milano began her career at age eight, after she won a role in an open audition for a national tour of "Annie", she was one of the four picked out of an audition with over 1,500 girls.
Split into simpler sentences: Milano began her career at age eight after winning a role in an open audition for a national tour of "Annie". She was one of the four picked out of an audition with over 1,500 girls.