Kylie isn't the only one in Kendall's family with a baby on the way. Her brother, Burt Jenner, is currently expecting a child, too.
"I always want to be the cool aunt and liked by all of them. There is 18 of them now, going on 20. There's two on the way," Kendall said. "... I have a lot of 'em. But it's fun. It's really fun. I try and be chill."
Just as Kendall loves being an aunt, her boyfriend, NBA player Devin Booker, likewise enjoys time with the kiddos.
"He loves them," Kendall said of her nieces and nephews. "Him and Stormi have an amazing relationship. She has the biggest crush on him, and I'm, like, jealous sometimes. I'm like, 'Stop.' I'm like, 'Can you guys not?'"
When they're not babysitting, the couple likes to get competitive by playing basketball together, including a recent game in the pool.
"He just, like, took it way too seriously. As did I, by the way," Kendall said of her beau. "I had the ball and he was guarding me and it was a whole thing. He actually ended up cutting my hand open a little bit with his nail, 'cause he took it too seriously... It was a big gash, and it bothered me for, like, two weeks."
"Devin Booker is sweet, smart, fun and totally not a player," the source said. "He is very respectful and was raised with very good values. Kendall finds that to be a very attractive quality."
"They're not putting any sort of pressure on things for the future," the source added. "They realize they're both still young and have big futures ahead of them. Right now they're just enjoying their time together and taking things as they come."