Seeing her older sister Kourtney Kardashian with a baby hasn't sped up Kim's maternal clock.

"I think it's actually slowed it down," she says on the Sept. 20 season premiere of The Rachael Ray Show (check your local listings). "It is so much work, and I really respect Kourtney for being able to work so much and still be such a hands-on mom."

PHOTOS: Kourtney Kardashian's son Mason shortly after his birth

Seeing her sib, 31, in mommy mode "has made me realize I can wait a little bit longer," adds Kim, 29. "I'm not ready, and I'm still in this self phase right now."