6-year-old Rihanna from the United States tops the list of young women with a net worth of 1.5 billion. For the third year in a row, pop star Rihanna has been named the richest man in America in 30 years. She is ranked 21st in the list of richest women but she is the first among women under the age of 30. Kim Kardashian has a net worth of 1.6 billion but is 31 years old. Rihanna became wealthy following her successful music career. The nine-time Grammy Award winner in 2014 says my money is not mine, I want to use it for people. The richest woman on the Forbes list is 6-year-old Diana Hendrix. He has a net worth of 12.5 billion.