You only turn 15 once, which might be why Kim Zolciak-Biermann didn't hold back when it came to celebrating Ariana Biermann's birthday on Monday. The Don't Be Tardy mom showed up at the teen's school and pulled out all the stops for for her daughter's big day, getting help from her party accomplice, Kroy Biermann.
Hours before the birthday surprise, Kim paid tribute to the teen on Instagram in a heartfelt message. "HAPPY BIRTHDAY to one of the most incredible people I know... my sweet @arianabiermann I can't believe you are 15!" she wrote. "My gosh where did the time go?! You amaze me each and everyday the person you are, the person you are becoming! I get so excited to think of all the amazing things you will do in your lifetime! Your heart is so pure. This world is such a better place with you in it! I hope you enjoy your day today.. (I might still show up with cupcakes at school) even though you are in high school! I love you to the moon and back a zillion times!! HAPPPPPPY BIRTHDAY MY SWEET ANGEL!"
Check out how much Ariana has grown up, below.