After more than a week of daily swim classes alongside mom, North clearly built up some confidence.
"She was so excited to have this apple that she would swim around the pool to get it," Kardashian said with a smile, sitting down with PEOPLE to promote her new line of sunless tanning products, Kardashian Sun Kissed, at ULTA Beauty in L.A. Aug 6.
Turns out North really wanted that apple.
"Then we took her out, and she just walked [her first steps] toward the apple!" Kim, 33, recalls of the moment both she and husband Kanye West, 37, were able to share together. “We were like, 'She walked!' It was so exciting!"
The reality mogul also reflected on her first few months as a newlywed and her first year as a proud mother.
"Obviously, [I] think her walking [was the biggest milestone]," says the reality star, 33. "And it's so fun to see her take swim class. She loves the water in general – she really likes to have fun."
For more on Kardashian and West's newlywed life and for an exclusive picture of baby North, pick up the new issue of PEOPLE, on newsstands Friday