It's a brand-new year, which also holds special significance for Catelynn and Tyler Baltierra: Their baby girl Novalee Reign is the big 0-1!

The "Teen Mom OG" munchkin, who made her grand entrance on New Year's Day 2015 and whose birth was later shown on the aforementioned series, is now in single digits and celebrating her very first birthday. And fittingly, the toddler's adoring parents took to Instagram to reflect on this special day and offer their darling daughter their well wishes.

"Happy birthday to my Tootie!!" the proud mama captioned the collage-style snapshot above. "I love watching u grow and learn! You are an amazing and smart little girl! I love you!!"

Meanwhile, Nova's doting dad shared a video of his Tootie when she was a newborn -- with an accompanying touching message about his petite gal and 2015.

"I can't believe a year ago today this special little moment with my daughter was happening," Ty began. "I can't believe the year 2015 blessed me in so many ways, with the birth of my daughter & the marriage to my childhood sweetheart. I am overwhelmed with the amount of love I have for my little family."

"This is all I have ever really wanted out of life...to be madly in love with my best friend, create & raise a child with her, & live every day like it was our last day together as a family!" he continued. "I love my wife @catelynnmtv & HAPPY BIRTHDAY TOOTIE FRUITEE! #TheBaltierraFamily #NovaleeReignsBirthday."

The longtime sweethearts, who outlined an adoption plan for their firstborn Carly on "16 & Pregnant" back in 2009, chronicled every step of their second pregnancy -- from learning they were expecting with a positive test result, a pink-filled gender reveal party, a baby shower, meeting their bundle of joy for the first time and much more.

Here's to many more milestones with sweet Baby N, Cate and Ty. Be sure to offer your birthday messages for the little lady of the day in the comments below, and catch a brand-new season of "Teen Mom OG," premiering on Monday at 10/9c! And for a sentimental rewind, watch the proud parents reflect on those initial moments with Novalee in the video below.