Kourtney Kardashian Falls Off Her Bike Into the Sand as She Goes for a Ride on Her 40th Birthday

Instagramming while bike riding is a recipe for disaster!

Kourtney Kardashian learned this the hard way after she fell Thursday during a ride on the beach with a few friends in celebration of her 40th birthday.

Kourtney documented the incident on her Instagram Stories, showing the exact moment she took a tumble on the Venice Beach bike path.

In the first clip, everything appears to be going smoothly as Kourtney pans the camera to show herself peddling in Vans Old Skool sneakers.

In the next clip, Kourtney’s pals can be heard screaming and laughing as the reality star lands in the sand on her back.

However, the Keeping Up with the Kardashians star was quick to dust herself off and hop right back on her bike — this time without her phone.

Prior to her eventful outing, Kourtney was showered with birthday wishes from her family and loved ones.

Kourtney’s mom Kris Jenner woke up bright and early to express how much her eldest child means to her writing, “Happy Birthday Kourtney!!! I can’t believe you are 40!! I love you more than you can ever imagine… you will always be my baby.”

Kourtney Kardashian | Kourtney Kardashian/Instagram
Kourtney Kardashian | Kourtney Kardashian/Instagram
Kourtney Kardashian | Kourtney Kardashian/Instagram
Kourtney Kardashian | Kourtney Kardashian/Instagram

“I am so blessed beyond words to be your Mommy and have you by my side in this precious life…you are my heart and I am eternally grateful for all of the memories that we cherish. I love you. Mommy xoxo.”

Along with the sweet message, Jenner, 63, posted a handful of photos from throughout Kourtney’s life, including one with her late father Robert Kardashian.

Khloé Kardashian, 34, also celebrated her sister’s milestone on social media, gushing about the “rare bond” they share.

“Happy birthday sweet @kourtneykardash!!! I am completely obsessed with each and every one of my siblings. Still blows my mind how blessed we are to call each other sisters. You and I have an incredibly rare bond that no matter what, it can never be broken,” she wrote. “You’re my best friend, one of the rare few I can count on most in my life. I’m so thankful for that.”

Kim Kardashian, 38, was next to give her sister a sweet shoutout.

“Happy Birthday @kourtneykardash I honestly can’t believe the life we have lived!” she captioned her post. “It’s such a dream to go through it all with having a sister like you by our side! You have taught me so much throughout life. You’re such an amazing mom and friend! Can’t wait to celebrate you tonight! I love you beyond what you could imagine.”

As Kourtney continues to celebrate, a source tells PEOPLE the reality star is embracing the milestone occasion and what the next year could bring.

“When she talked about turning 40 a while back, she didn’t seem too excited,” says the source. “Turning 40 is a big deal. But instead of seeing it as something negative, Kourtney turned it around and she seems very excited about her life just in general.”

After launching her lifestyle website Poosh last month, the source says Kourtney has a newfound sense of pride in her work.

“She feels great about many things that she has accomplished so far,” says the source. “She is very excited about Poosh. She has been very focused on it. She has a small team that helps out, but she’s putting in many hours making sure her site is fun, educational and features brands that she loves.”

While her professional life soars, Kourtney is also content with her personal life. A second source tells PEOPLE that while Kourtney is dating, she’s careful about who she brings into life now that she’s found happiness within herself.