Viewers of the MTV series have watched little Jace grow up on our screens and we can hardly believe he's now big enough to be at school!
But today Jenelle tweeted: "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 he is so smart they are having him do 1st grade math already!
"My little man is SUPER SMART!"
Over the weekend, Jenelle spent time with little Jace at the beach, sharing some very sweet photos of him to Twitter.
In one image, she simply wrote: "He melts my heart to a puddle."
Former wild child Jenelle recently became a mum for a second time after giving birth to son Kaiser, her first child with boyfriend Nathan Griffith.
During a recent fan Twitter Q&A with MTV, Jenelle said of her little family: "Jace loves the fact he is finally a big brother now. He tells all of his friends at school he has a baby brother named Kaiser."
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Stars who welcomed babies in 2014:
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