Credit: Instagram

Sigh, they grow up so fast! It seems like just yesterday that Teen Mom 2's Kailyn Lowry popped out the cutest kiddo in the world (aka Baby Isaac), and now he's a whopping 3 years old! Isaac turns 3 today, January 18, and Kailyn has taken it to the interwebs to tell the world that she loves her little man to infinity and beyond!
 
"Words cannot describe the love I have for my son," Kailyn posted to Instagram on January 17, along with some seriously adorable pictures of Isaac. "January 18th, 2010 was the happiest day of my life. I cannot believe my baby is 3 tomorrow! #happybirthday."
 
Kailyn and Isaac have a big day planned, but sadly Kail's hubby won't be around to join in on the fun. "Tomorrow Isaac is 3 & a month that @JaviM9's been gone," Kailyn tweeted. "Isaac keeps saying Javi will be at the aquarium with us. </3"

Javi is currently at Air Force boot camp, but we're sure he'll find time to wish Isaac a happy birthday. Either way, this kiddo is destined to have a super day full of Toy Story-themed adventures!

Source: Instagram / Twitter