Kylie Jenner Is Insecure About Post-Baby Body at First Photo Shoot Since Stormi: ‘I’m 158 Lbs.’

Kylie Jenner‘s post-baby body journey is unfolding on this season of Keeping Up with the Kardashians.

In a sneak peek at Sunday’s  episode, Kylie, 21, admits to feeling insecure as she prepares to pose for a Calvin Klein campaign with her sisters — her first photo shoot since welcoming her first child, daughter Stormi, with Travis Scott on Feb. 1.

“This is going to be my first photo shoot after Stormi and doing my first few fittings and getting back into it, it’s kind of hard and discouraging,” she says.

“Kylie, you look amazing,” Khloé Kardashian, 34, reassures her sister. “And your belly button is back to normal!”

“I’m still 158 [lbs.],” Kylie responds.

“Me too!” Kris Jenner says, high-fiving her youngest daughter.

“[I’m] 198 [lbs.], right now. So do you want to f—ing play this game?” says Khloé, who was then pregnant with her first child, daughter True.

“Kylie, I’m not kidding, you look insane,” chimes in Kourtney Kardashian, 39.

“Your body looks f—ing crazy,” Khloé insists.

“It just doesn’t,” Kylie responds.

 The new mom gave fans their first glimpse at her post-baby transformation just seven weeks after giving birth to her daughter, posting a quick video on Snapchat of herself lifting up a black hoodie to expose her stomach.

About one month later, she was already back in a bikini — and since then, she’s often showed off her toned physique on social media.

In March, Jenner revealed that she gained a total of 40 lbs. during pregnancy in a since-deleted tweet.

Sources previously told PEOPLE that Jenner is determined to get back into pre-pregnancy shape because she wants to be a “really hot young mom.”

“Kylie is already starting to work out,” an insider said. “She’s focusing on getting her body back and also getting back to a comfortable weight aside from caring for Stormi.”