How old 14 of the world's richest people were when they first became billionaires

Today's estimated net worth: $5.7 billion

Lucas may be the brains behind two of the most well-known film franchises of our time, but he made most of his money by selling his production studio Lucasfilm to Disney for $4.05 billion in cash and stock in 2012, according to Bloomberg. He first became a self-made billionaire in 1996 at 52.

Today's estimated net worth: $51.2 billion

The Telecom magnate became a self-made billionaire in 1991 at 51. Real-estate investments contributed to Slim's fortune. In 2015, he was the second-richest person in the world.

Today's estimated net worth: $71.4 billion

The founder of Oracle became a self-made billionaire in 1993 at 49, Business Insider previously reported. Since stepping down as Oracle's CEO in 2014, Ellison has earned a reputation as a jet-setting, yacht-racing playboy.

Today's estimated net worth: $2.5 billion

The media mogul and queen of daytime television became a self-made billionaire in 2003 at 49, per Forbes. Winfrey's media empire led her to become the first Black female billionaire in history, Business Insider previously reported.

Today's estimated net worth: $4.6 billion

Britain's high-profile billionaire earned his first billion in 1991 at 41, per Forbes. The Virgin Group founder became a self-made billionaire thanks to the success of his many companies — he has overseen approximately 500.

Today's estimated net worth: $4.2 billion

The "Shark Tank" investor and Dallas Mavericks owner became a self-made billionaire in 1998 at 40, per Forbes. Selling his first company, Micro Solutions, made Cuban a millionaire — selling his second company, Broadcast.com, made him a billionaire.

Today's estimated net worth: $113.5 billion

The Microsoft cofounder and noted philanthropist, now 64, became a self-made billionaire in 1987 at 31. When the value in Gates' shares surpassed $1 billion, he became the youngest billionaire ever at the time, Business Insider previously reported.

Today's estimated net worth: $66.8 billion

Google's cofounder, now 47, joined the three comma club in 2004 at age 30, when the company's IPO sent Page's net worth over $1 billion for the first time.