My high level students discovered how Kylie Jenner has become a billionaire at the age of 21. Entrepreneur, social media star and model Kylie Jenner has done just that. According to the business magazine 'Forbes', Ms Jenner has become the world's youngest self-made billionaire. She is so successful that she became a billionaire two years younger than Facebook founder Mark Zuckerberg. Jenner is the youngest sibling in the Kardashian family.