Kylie Jenner is the world's youngest billionaire, according to Forbes.

Per the business magazine's ranking of the richest people in the world, the reality TV star and beauty and fashion entrepreneur has an estimated net worth of $1 billion. At 21, she's the youngest self-made billionaire.

Although many are quick to question the “self-made” aspect, Forbes has clarified its use of the term as “someone who built a company or established a fortune on her own, rather than inheriting some or all of it.”

According to the publication, “As long as the list member didn’t inherit a business or money, she is labeled self-made. But the term is very broad, and does not adequately reflect how far some people have come and, relatively speaking, how much easier others have had it.”

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In the case of Jenner, she got a head start from wealthy parents -- Olympian and TV personality Caitlyn Jenner and reality TV personality and businesswoman Kris Jenner -- and a moneyed background.

In a February interview with Paper magazine, Jenner emphasized that she is in fact self-made: She was cut off by her parents when she was 15.

“My parents told me I needed to make my own money, it’s time to learn how to save and spend your own money, stuff like that,” she said. “What I’m trying to say is, I did have a platform, but none of my money is inherited.”

Jenner’s cosmetics line has contributed to most of her wealth, particularly in August 2018, when the mother of one signed an exclusive distribution deal with beauty retailer Ulta.

Kylie Jenner visited an Ulta Beauty location in Houston, Texas to celebrate the exclusive launch of Kylie Cosmetics in Ulta Beauty stores nationwide and online at ulta.com in November 2018.

Credit: Rick Kern/Getty Images

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Credit: Rick Kern/Getty Images

Before then, Jenner used her existing social media reach to propel the company, marketing products on her Instagram, Snapchat, Twitter and Facebook profiles when the company started in 2015. At the time, Kylie Cosmetics only offered lip liner and lipstick lip kits for $29.

“It’s the power of social media,” Jenner said. “I had such a strong reach before I was able to start anything.”

Now, the company offers eye shadow, eyeliner, highlighter, bronzers, blushes, palates, concealers and accessories.

“I see (Kylie Cosmetics) going very far,” Jenner said. “I work really hard.”

At 21, Kylie Jenner is the youngest billionaire in the world, according to Forbes.

Credit: Matt Winkelmeyer/Getty Images

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Credit: Matt Winkelmeyer/Getty Images

According to estimates from investment banking company Oppenheimer, Kylie Cosmetics sold $54.5 million worth of products at the retailer over six weeks. According to Forbes' estimate, Kylie Cosmetics is worth at least $900 million, and she owns her entire company. Adding in Jenner's other income, she is, by the publication's ranking, the youngest billionaire.

“I didn’t expect anything,” Jenner said. “I did not foresee the future, but it feels really good. That’s a nice pat on the back.”

More on Jenner's business, including the inner workings of Kylie Cosmetics, is at Forbes.com.