Catelynn Lowell is marking a major milestone.

The Teen Mom: The Next Chapter star celebrated her firstborn Carly's 14th birthday on May 18 with a sweet tribute on Instagram.

"14 years ago this amazing little girl was born!" she wrote alongside a series of throwback photos. "Gosh if she only knew how many people she has touched and changed. Happy Birthday Carly. We love you so much!!!" 

Fans first met Catelynn and her now-husband Tyler Baltierra on the first season of 16 and Pregnant in 2009, during which she gave birth to Carly and they placed her for adoption. She was adopted by Brandon and Teresa Davis, and viewers continued to watch Catelynn and Tyler's journey unfold on Teen Mom and its spinoff series, where they've spoken about their relationship and visits with Carly.

"I think it's awesome to be able to show the journey of an open, semi-open adoption through the years and the ups and the downs and learning and navigating this relationship," Catelynn told E! News in October 2021. "I think it's super awesome that we can continue to do that in a way that can show our fans the journey but also in the way that it allows Carly's parents to feel comfortable with us sharing it as well." 

Tyler agreed. "Before our 16 and Pregnant aired, I've never really heard about adoption, let alone open adoption," he added. "I feel like we did a good job of opening the door for that conversation to happen and making it more normal, more accepted to get information. It's kind of great to think about being part of that door opening, but we're blessed to do it."

And in a 2022 episode of Teen Mom: The Next Chapter, Catelynn and Tyler, now 31, shared their story with their daughter Novalee, 8.

"When mommy found out she was pregnant, me and daddy talked and we said we can't raise a baby right now," she said. "We didn't have cars. We were still in school, no jobs."

Catelynn—who also shares kids Vaeda, 4, and Rya, 20 months, with Tyler—has previously spoken about how they stay in touch with the Davis family.

"We text back and forth," Catelynn told E! News in September 2021. "We send pictures. I send pictures of my girls to them, and they send pictures of Carly to us and updates on what they are doing and vice versa."