A source tells ET that the reality star "is doing well and is happy."
"Kylie always wanted to be a young mom," the source says. "She may be young, but she's very maternal and has lots of practice with babies! She's a very hands-on aunt and was basically a step-mom to Tyga's kid."
Jenner has previously talked about wanting to have children at a young age.
In April 2015, a then 17-year-old Kylie said she hopes to be a mom by 27. "When I look to the far future and decide to have kids, I need to have a million girls," she told Teen Vogue. "Ten years from now -- in 2025 -- I hope I have a kid."