6. Madonna
Did you know Madonna began her run in entertainment by first pursuing a career in dance? After graduating high school, she received a dance scholarship to the University of Michigan, but later dropped out to move to New York City at the age of 20. She eventually took classes at Alvin Ailey American Dance Theater. 

Fast forward five years and Madonna was already a star. In 1983, she released her debut self-titled album, and in 1984 she released Like a Prayer — two releases that sandwiched her 25th birthday.