Just ask Maci Bookout, Amber Portwood and Jenelle Evans: One day, your kids are in diapers. The next, they're starting kindergarten.

The "Teen Mom" and "Teen Mom 2" cast members recently sent their adorable offspring to school -- and shared updates on their social media accounts about the super-exciting time. Bring on the sharpened No.2 pencils and fresh crayons -- and in one case, the Kleenex.

Bentley, for one, may have been smiling on his first day of kindergarten, but his mama's reaction was an entirely different story: "I seriously thought I could make it through the first day kindergarten without a melt down LOL I didn't even make it out of the parking lot," she wrote on Twitter.

Meanwhile, Amber, who recently admitted that she needed her girl Leah to "stop growing," re-tweeted Gary's photograph of their semi-toothless daughter as she made her way inside to meet her classmates.

Lastly, Jenelle marveled at her son's achievements on his first day of the big K. You go, Jace!

"IM SO PROUD OF JACE! He just started his first day of school. He didn't know why they took him out of class for math.. Well we found out," she tweeted, before continuing, "he is so smart they are having him do 1st grade math already! my little man is SUPER SMART!!!!!!"

Offer your well wishes to the new students in the comments below. Then be sure to keep watching Jenelle and Jace on "Teen Mom 2" on Wednesdays at 10/9c, and stay tuned for more updates on the return of Maci, Bentley, Amber and Leah!

Design by Akiko Yamamoto