Kendall Konfession: Jenner Admits She 'Grew Up Too Fast' – Feels 'Scared' To Turn 20

Kendall Jenner is just 19, and has several nude photo shoots behind her. Now, for the first time, the reality star turned model is admitting she grew up too fast.

"I feel like I grew up too fast a long time ago," the reality star wrote, who has rapidly made a name for herself in the modeling world, wrote in a new column for WSJ magazine.

While she grew up on her family’s reality show Keeping Up With The Kardashians, Jenner attributes her sudden rise to adulthood to her family's work ethic, not their fame.

"Having older siblings, you grow up around adults, so you mature more quickly," she continued. "I saw my sisters and parents working every day, so I was pretty much brought up to be a workaholic. But I just turned 19 a couple weeks ago, and I'm scared to be 20 -- it's the first step out of being a teenager."

"My sister Khloé always says to me and my younger sister, Kylie: 'You have your whole life to be an adult but only so long to be a kid,' Jenner wrote. "And we get it. In the right situations, I try to be as immature as I can sometimes – react to things as if I were 12. You can't take things too seriously. I just laugh thinking about my dad being a teenager, partying. It's the funniest thing. And it makes me think – what am I going to be like when I'm 65?"

The new face of Estée Lauder, the Jenner has entered the biggest endorsement deal of her career to date and continues to be an Instagram sensation.