Jessica Simpson's Kids Maxwell, 10, and Ace, 9, Look All Grown Up in First Day of School Photo

Jessica Simpson Instagram

Jessica Simpson's kids are heading back to the classroom.

On Wednesday, the singer, 42, shared a sweet photo on Instagram of her older two kids, daughter Maxwell Drew, 10, and son Ace Knute, 9, on their first day of school.

In the heartwarming picture, which is missing Simpson and husband Eric Johnson's younger daughter Birdie Mae, 3, Maxwell wraps her arm around her younger brother as the siblings pose in the driveway, showing off their first day of school outfits.

"These two had an amazing first day of school! I'm so proud! Heart is full. Growin' up and ownin' it. Happy kiddos," Simpson captioned the cute shot.

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Before heading back to school, Maxwell had the opportunity to help her mom promote her Jessica Simpson Style roller skates by modeling the new line.

Maxwell was a major fashionista in the promotional photos as she showed off the rose gold multi skates that were covered in fun sequins. She paired them with white pants and an oversize Johnny Cash concert t-shirt and wore her long blonde hair in pigtail French braids.

In April the "Irresistible" singer told PEOPLE about some of the lessons she's learned from Maxwell. "My oldest daughter, who's nine; she's about to be 10; she teaches me a lot about self-love, to be honest," she said. "She is so cute and so adorable and so confident and just owns it."

She noted that her daughter is "one of those girls that's going to be a trendsetter, a leader and manifest everything."