"I don't think being a new mom changed me, I think it just maybe made me look at life a little differently and just value time," 20-year-old Kylie -- who has a 5-month old daughter, Stormi, with boyfriend Travis Scott -- says in the clip.
Kim -- a mom of three to North, 5, Saint, 2, and Chicago, 6 months -- has learned that the best advice doesn't always come from the oldest or most experienced people.
"I thought I knew the best car seat and then Kylie showed me a better car seat and so I was really grateful for that," Kim, 37, reveals. "Being a mom, honestly, just makes you not really give a f**k about anything else, but, like, immediately what's going on inside, in your home."
After welcoming her daughter, True, back in April, 34-year-old Khloe has come to appreciate her sister Kim's advice the most.
"My sister Kim probably gives the best advice because it's the least judgmental," Khloe shares. "She's offering information and you can take it or don't, but I love that she says, 'You know, you're not going to know what kind of mom you are.'"
ET caught up with Kim back in April -- before Khloe gave birth -- and she revealed that she was already giving her then-pregnant sister the best parenting advice.
"Khloe and I have a really good thing going on right now," Kim said at the time. "I'm like the real one with her [about] what goes down and how it's going to go down."
Kim continued: "She's seen all of us go through it. She's prepared, but I feel her and I are on a really good communication about everything. I know when to push it and when to... right now isn't a time to freak her out. The closer it gets, you can't freak someone out."