Pregnant Kourtney Kardashian says little sister Kim thought she'd be the first Kardashian sib to become a mom.
"She definitely thought it was going to be her first. Kim has, like, every baby name picked out," Kourtney said on Ryan Seacrest's KIIS-FM radio show this morning.
"Kim...I don't think she was envious, but who knows," Kourtney went on of her sis, who recently split from Reggie Bush. "Kim gets mad if I get, like, the car that she wants. She, like, freaks out.
"Out of all of us, I was definitely the last one that was even thinking about it," Kourtney confessed, adding that she's due around Christmastime -- the same period as another E! reality star, Kendra Wilkinson.
Kourtney says she had her sister Khloe tell the family she was expecting.
"I was just, like, so nervous," she said. Stepdad Bruce Jenner was "the most realistic," she says. "[He said], 'You guys are acting like you're getting a little puppy dog! You need to take this seriously'.... He freaks me out the most."
Getting pregnant with Scott Disick – with whom she recently reunited after splitting in February – was unplanned.
"This probably sounds so dumb, but there's so many times I'll forget to take my pill and I don't think it's that big of a deal. It's just so stupid," she admitted.
Kourtney says she had an inkling she was pregnant after getting "really nauseous, like, suddenly...not just in the morning. I would have to eat Saltines at all times in the day."
On her new reality show – Kourtney and Khloe Take Miami (premiering Sunday) – she literally gets sick in a club, she said.
Her boobs also became "huge and they were so sore."
Now that she's about five months along, Kourtney explains how she dresses her bump: "I just wear jeans and keep them unbuttoned and wear a big shirt."
(She's also opening a new store in California "soon," she says: Dash for Babies.)
Kourtney says she's brainstorming names for either a boy or girl – and dropping the "K" alliteration her siblings share.
"It's so hard. I'll think of something and it just goes away," she said. "And everyone is asking what we're doing with the last name: Kardashian or Disick. I don't know [if we're getting married]. We've talked about it. I feel like there's so much going on, but I don't know if I can even go there."
The baby may be incorporated into the second season of her reality show, she joked.
"Kourtney and Khloe in Japan...With a baby!" she quipped.