Kourtney Kardashian turns 37 Monday

By Aurelie Corinthios
Updated April 18, 2016 09:30 AM
Source Instagram

brightcove.createExperiences(); Happy birthday, Kourtney Kardashian!

The Keeping Up with the Kardashians star turns 37 Monday, and her momager Kris Jenner took to Instagram to celebrate her daughter with a sweet throwback photo of her, Kourtney’s late father Robert Kardashian and baby Kourtney from back in the day.

“Happy Birthday tomorrow beautiful @kourtneykardash!! I know it’s crazy but I remember this pic like it was yesterday,” wrote Kris, 60. “You have brought so much love, joy, and happiness into my life and I’m proud to be your Mom.. You teach all of us everyday what it means to be an amazing daughter, Mom, sister, friend, and a genuinely beautiful human being. Thank you for being such a bright light and an inspiration to me every day.. You are kind and patient and have the biggest heart and I love you more than you will ever know.”

“You will always be my firstborn who captured my heart…. Oh, and I’m really sorry about this outfit I put you in….I love you, mommy #love #blessed #mybaby,” she added.

Kris, 60, also shared a sweet collage of baby pictures of her eldest daughter.

“Happy birthday @kourtneykardash!! Enjoy this special day! I love you!! #mybaby #love #family.”

Sister Kim Kardashian West also took to Instagram to wish Kourtney a happy birthday, sharing an old throwback of the two in matching outfits.

“Happy Birthday @kourtneykardash Thank you for always doing everything first so I can copy you!” wrote Kim, 35. “I don’t know what I would do without you! I love you! Happy Birthday!”

She also added a message for Kourtney on her website and app, writing: “Happy birthday, Kourt!!! I feel really lucky to have you as my big sister. You’ve always been there for me, and I’m constantly turning to you for mom advice. Plus you’re the best workout partner LOL. Love you!”

Khloé Kardashian also shared her own Instagram post.

“Happy birthday @kourtneykardash!! What would our family do without you?!?!” wrote Khloé, 31. “This picture sums us up, even though I’m covered in chicken pox, you’re still chillin by my side. I love you!!!”

“Happy birthday, my soulmate!!!” Khloé gushed on her website and app. “Kourtney, you are my best friend and I couldn’t ask God for a better big (little) sister. I’m thankful everyday to have you in my life. You have know idea how much I love and admire you! You’re 100 percent real, all the time. My life would be nothing without you in it!!! Happiest birthday to the yin to my yang, the Bey to my Jay, the milk to my cookies, the Lady to my Tramp, LOL!!! Love you, Kourt!”

Chimed in sister Kendall Jenner, 20: “Happy Birthday Kourt!!! I love how well we get along since we’re so similar. It’s amazing to have a sister and role model like you in my life. I love you so much. You’re the best!”

Kylie Jenner, 18, also posted her own birthday message.

“Wishing my big sister Kourtney the happiest birthday! Love you, Kourt!” she wrote as the caption to a sweet video montage of the two on her website and app.

Kourtney, meanwhile, is busy celebrating on vacation in Iceland with Kim and her hubby Kanye West, plus a few other family friends.

A source told PEOPLE last week that the reality star and mother of three is “doing great,” and that while “last year was very tough for her” following her split from Scott Disick after nine years, she acts “happier and confident lately.”

“It took Kourtney months to get to where she is right now,” added the source.