The Gosselin sextuplets are officially teenagers

Time flies. Kate and Jon Gosselin's eight children are all teenagers!

Aaden, Alexis, Collin, Hannah, Joel and Leah Gosselin turned 13 on Wednesday. The old Jon & Kate Plus 8 stars – and current Kate Plus 8 stars — have officially joined their 16-year-old twin sisters, Madelyn and Cara, in the teenage world. Do you ever feel old?

Given Kate and Jon's strained relationship since their divorce, it should come as no surprise that the family didn't celebrate together.

“I had four: Hannah, Leah, Joel and Aaden,” Jon told E! News from their celebration on Monday. “I would cook hamburgers and hot dogs on the grill, and we would give presents and play soccer in the backyard. After that we made cake and ice cream. It was good.”

Despite Alexis and Collin's absence from the festivities, their names were still on the birthday cake.

Kate posted her own celebratory message on social media, writing a touching message to her children.

“HAPPY 13th BIRTHDAY, my precious Alexis, Hannah, Aaden, Collin, Leah and Joel! At this moment (7:51-7:53), 13 years ago, my life and my heart were completed with your births! she shared alongside a collage of photos of the sextuplets showing just how big they've become.

Kate continued: “I love you all and no matter what it takes of me, I will ALWAYS be here for you; I will always be your biggest cheerleader, your role model, your shoulder to cry on, the hug and laugh you need, and your mom and friend! I love you! I got six times what I expected, but I would NEVER go back! You are the last six pieces of my heart that I never imagined looking for…”

Kate concluded with the hashtags “#Turning13Today #HappyBirthdayBabies #ILoveYouToTheMoonAndBack100MillionTimes.”

She also made cinnamon rolls that the sextuplets shared with their classmates:

It's been a sentimental week for the matriarch. On Tuesday evening, Kate shared a memory she's had for 13 years.

“Sitting in my room with the kids…thinking back to almost 13 years ago. I took this very small preemie diaper out of the NICU,” she captioned the photo above of the small diaper. “I kept it in my bedside table drawer, wherever we went… to always remind me of how far we’ve come!! The children were impressed! #Preemies13 #Preemies #TwentyNineAndFive #TwoAndThreePounds.

Children… they always grow up too quickly.

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