World’s youngest self-made female billionaire Lucy Guo began hustling in elementary school

Her entrepreneurial instinct began in primary school, where she often sought ways to earn as her frugal parents instilled the importance of financial security. "They always emphasized that having money is important, so I would find ways to make money on the playground," Guo said in a recent interview with CNBC Make It.

"I would up trade Pokémon cards and then sell them. I would sell colored pencils, anything I could find."

Guo recalled that her strict parents sometimes confiscated her cash when she misbehaved. To protect her savings, she got a debit card from retail store Home Depot in second grade and opened a PayPal account.

Her ventures grew more sophisticated over time. A fan of the online game Neopets, she began selling rare pets and in-game currency for real cash. "I would get rare pets, rare items, and resell them for actual cash," she said.

Later, she discovered coding and developed bots to cheat in games, which she sold for profit, before moving on to websites, Google AdSense projects, and internet marketing tools. "It just snowballed from there," she said.

Billionaire Lucy Guo. Photo courtesy of Guo's Instagram

At 22, the Carnegie Mellon University dropout co-founded Scale AI with Alexandr Wang, a former Quora colleague. The company, which labels data for artificial intelligence systems, sold a 49% stake to Mark Zuckerberg’s Meta for $14.3 billion earlier this year, according to Bloomberg.

Guo left Scale AI in 2018, but her stake in the company had already secured her billionaire status. The 30-year-old has a net worth of $1.3 billion, according to Forbes.

In 2019, she founded Backend Ventures, a venture capital firm that invests in early-stage tech startups. She is now building Passes Inc., a platform that helps celebrities and creators monetize fame by offering exclusive content such as one-on-one calls, video chats, and direct messages, British newspaper Metro reported. The app, which allows creators to keep about 90% of their earnings, has already produced "a lot of millionaires," Guo said.