Jill Duggar Shares Photos from Son Israel's First Day of First Grade: 'We Couldn't Be Happier'

Jill Duggar Dillard's children are growing up before her very eyes.

The Counting On star, 30, took to Instagram on Monday with photos from 6-year-old son Israel David's first day of first grade. "1st day of 1st grade was last week for this big guy! Its hard to believe we are already here!!" she started in the caption.

Jill and her husband Derick Dillard, 32, share sons Israel and 4-year-old Samuel Scott. The family added another member back in March, announcing that they adopted a dog, whom they named Fenna.

"Israel loved walking Fenna to school on his first day & she was super happy too, but got a little concerned after he walked inside…she stood there and kept watching for him. Israel's kindergarten teacher moved up with him to 1st grade this year and we couldn't be happier!" Jill continued. "Sam is super happy to be getting some one-on-one time with mommy in preschool at home & on-the-go with regular library visits and fun classes they offer!"

The family previously starred in Counting On, TLC's spin-off of 19 Kids and Counting, before they exited the show in 2017. Jill opened up to PEOPLE about the decision to leave the series in October.

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"We just wanted more control of our own lives," she said. "There was a certain job that we had been working towards for, even before we were married, that was taken away from us."

Jill added: "It didn't go over very well with anyone. By that point we'd had enough. We knew we had to pull out completely to reevaluate and get our bearings."