Credit: Instagram Photo: Catelynn Lowell and Tyler Baltierra Ring in the New Year

Catelynn Lowell and Tyler Baltierra might just be the best parents in Teen Mom land!

These high school sweethearts were faced with a tough decision when they welcomed their daughter into the world at the tender age of sixteen, but they ultimately placed her for adoption with a loving family. Luckily, Cate and Ty have been an active part of Carly's life thanks to their "open adoption" (where they can communicate with their kiddo through email, phone calls, and the occasional in-person visit), and they recently celebrated their baby gal's fourth birthday!

"4 years ago today, my life changer, my inspiration, my motivation was born. HAPPY BIRTHDAY CARLY! I love you beyond understanding," Tyler tweeted on May 18, while Cate added "Wow my daughter turned 4 today exactly at 10:39 on the morning. I thank god for her. She pushes me along everyday! #happybdaycarly. I love u!"

It's amazing how much Carly has influenced Cate and Ty's life. Not only did Cate and Ty  become advocates for adoption, they frequently tour the country to speak about their adoption story, and have helped many teen parents through the process.

Hopefully, Cate and Ty will be able to reunite with Carly soon. Who knows, maybe she'll even make an appearance at their upcoming wedding! Flower girl, anyone?

Source: Twitter/Twitter