Little Penelope Disick just turned five and she's already living her best life.

Kourtney Kardashian and Scott Disick's too-cute daughter celebrated her fifth birthday on Saturday, and she spent the weekend enjoying her favorite things: mermaid cakes, giant balloons, tutus, and her cousin/BFF North West. Even though the extended Kar-Jenner family marked both girls' birthdays with a joint Moana-themed bash two weeks ago, that didn't stop them from treating Miss. P on her actual birthday, too.

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First, Princess Penelope hosted a slime-making class. In a series of videos shared by mom, Kourtney, the adorable young lady attempts to instruct viewers on how to make slime. There's just one problem: she's not entirely sure how to do it.

Kourtney also shared a photo of Penelope surrounded by giant white balloons. "I can not believe my baby girl is 5 years old today," she captioned the 'gram. "Happy Birthday my sweet angel. I feel so blessed to be her mommy every morning that I wake up next to her." At some point during the day, the birthday girl had a wardrobe change, and later posed for a hilarious photo in a ballet costume. If we're not mistaken, she might even be wearing a lipstick from aunt Kylie's coveted Lip Kit.

It was a tough decision, but our favorite part of the day was documented by four-year-old North's mom, Kim, who caught the girls getting ready for Penelope's party. In an Instagram video, the cousins can be seen clomping around a palatial closet wearing adult-sized pumps.

"We're going out to go to a party!" North exclaims. Penelope, who paired a pink satin nightgown with clear pumps, explains to her aunt Kim that there will be balloons, a mermaid cake, and 97 live mermaids at the party. North adorably chimes in to say that there will also be a "shower and towels."

Happy birthday, P! It looks like it was a good one.