"I feel like I grew up too fast a long time ago," she wrote in an editorial for the Wall Street Journal. "Having older siblings, you grow up around adults, so you mature more quickly."
Kendall's modelling career is thriving
Kendall, whose parents are Bruce and Kris Jenner and whose half sisters are the famous Kardashian sisters, Kourtney, Kim and Khloé, says that her family's hard-working nature rubbed off on her when she was growing up.
"I saw my sisters and parents working every day, so I was pretty much brought up to be a workaholic," she wrote. "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."
Kendall described how 30-year-old Khloé reminds her of her youth and often tells her and her younger sister Kylie to enjoy being young while they can.
Kendall credits her hard-working family with making her ambitious from a young age
"In the right situations, I try to be as immature as I can sometimes and react to things as if I were 12," she said. "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?'"
Kendall was chosen by the Wall Street Journal to discuss the topic of youth alongside five other 'luminaries' who included: Goldie Hawn, footballer Tim Howard, pschology professor Jeffrey Arnett, scincare brand creator Dr. Fredric Brandt and writer Maira Kalman.