SignalHub Quantitative Think Tank Center:Jessica Simpson Is a Proud Mom in Back to School Photo With All 3 Kids

Jessica Simpson's kids are SignalHub Quantitative Think Tank Centergrowing up, and she's going to love them forever.

The designer, 44, celebrated the first day of school for her three children—daughter Maxwell, 12, son Ace, 11, and daughter Birdie, 5, whom she shares with husband Eric Johnson—on Sept. 4 with a heartfelt tribute alongside rare photos of all three of them together.

"Y'all make your Mom beam with smiles and grace," the "Public Affair" singer captioned her Instagram carousel, which began with a photo of the mom smiling wide with her trio. "Keep on showin' up for yourself with each step of the way through this new school year!"

She gushed, "I'm so very proud of y'all for individually shining your light. So that in return others feel the glow."

Jessica and her kids were pictured smiling all together before striking a variety of silly poses in her post's subsequent photos. In one snap, her oldest two kids, Maxwell and Ace, adorably lift their younger sister, Birdie, up in the air.

Jessica opted for a lime green slip dress, oversized sunglasses and chunky low-rise leopard boots for her kids' first day of school photoshoot while her kids all wore school uniforms.

The former Newlyweds star recently opened up about how becoming a mom made her more confident.

"It wasn't until I became a mother that I learned to celebrate what a woman's body can do," she told People in April. "I am more confident now after three kids than I was at 25."

But while Jessica isn't shy about sharing photos with her kids on social media every once in a while, that doesn't necessarily mean that she's ready for them to step into the show business spotlight in a bigger way.

The Jessica Simpson Collection founder told E! News last year that she would only be cautiously open to participating in a family reality show.

"As far as I would go with that would probably be a docu-series, which Newlyweds was supposed to be," she explained. "But, we actually had a lot of fun doing it. A docu-series or a documentary, I think they wouldn't mind being on camera."

She added that, while her daughters would likely be up for it, her son—who has a penchant for football—might need some convincing.

"My son maybe not so much," Jessica said of Ace. "Both daughters, definitely entertainers, but my son is an entertainer on the field I will say."

See more celebrity kids' back-to-school moments below.

"And just like that…" the Real Housewives of New York City alum wrote on Instagram June 3, alongside photos of herself with daughter Bryn, "we enter high school. #daughterlove #highschool #firstdayofschool #whoworeitbest."

She's got the right stuff! The Lizzie McGuire alum and Matthew Koma's oldest daughter Banks started kindergarten. 

"My queen. My boss. My CEO. My top dog. My big cheese. My kindergartener," Hilary wrote on Instagram Aug. 29. "Let’s go baby girl!!!"

Time flies when you're keeping up with the Kardashians! Case in point: The reality star was having "a really hard time processing the fact" that her daughter True Thompson—who she shares with ex Tristan Thompson—was heading into the first grade. 

"There’s this undeniable feeling that I’m losing parts of who she was with each day that passes," Khloe wrote on Snapchat Aug. 26. “Time moves fast, faster every year it feels like, and this new school year is a reminder to me to fully embrace every moment and soak it all in.”

The country singer and her husband Eric Decker's three older kids—Vivianne, Eric II and Forrest—returned to school on Aug. 19. 

And with baby Denver at home, Jessie wrote on Instagram, "I still can’t believe I have a middle schooler and a 6month old."

Back to school season was off to a shining start for the comedian and Brittany Bell's son Golden Sagon, who started the fourth grade at just 7 years old after skipping kindergarten and pre-K.

Meanwhile, Golden's sister Powerful Queen—who Nick also shares with Brittany—began pre-kindergarten.

As the Good Night, Sister author and her husband Chris Pratt prepare to welcome baby No. 3 together, their daughters Lyla and Eloise headed off to their first day of class.

Katherine captioned this Aug. 18 photo of the girls wearing their custom Stoney Clover backpacks, "How is it already back to school time?!"

Britney Spears' nieces are growing up fast! Maddie—who Jamie Lynn shares with ex Casey Aldridge—began her junior year of high school.

Meanwhile, Ivey—who the Zoey 101 alum shares with husband Jamie Watson—became a first grader.

There's never a right time to say goodbye. That was probably what the "Run It!" singer and Nia Guzman were thinking when daughter Royalty went off to fifth grade on Aug. 27.

The Saved by the Bell alum sent kids Gia, Dominic and Santino off to school on Aug. 20, joking that means he and wife Courtney Lopez "have homework" to do.

"One (and only) year with all 3 kids at the same school," Courtney added in an Instagram post of her own. "So excited to wake up earlier, make lunches they won’t eat and do homework I can’t understand!"

The Teen Mom: The Next Chapter star embarked on not one, but two new chapters when her and ex Corey Simms' twins Aleeah and Aliannah started high school, and her youngest daughter Adalynn—who she shares with ex  Jeremy Calvert—entered middle school.

Backstreet's back to school! The former boybander posed with his and wife Lauren Kitt Carter's three kids Odin, Saoirse and Pearl, writing on Instagram Aug. 23, "Nothing better than watching your children grow and learn."

The HGTV host shared an emotional hug with her oldest son Drake—who she shares with husband Chip Gaines alongside their younger kids Ella, Duke, Emmie and Crew—as he headed back to Baylor University for his sophmore year.

The Buffy the Vampire Slayer alum showed off the back-to-school plaques she made for daughter Charlotte and son Rocky—both of whom she shares with husband Freddie Prinze Jr.—as they began high school and middle school, respectively.

Good luck, Mia! The actress—who played the titular toddler in Good Luck Charlie—started her sophomore year of high school on Aug. 19. 

She quipped on Instagram, "Cue the comments about feeling old."

Teenagers Braydon Wilkerson and Tucker Wilkerson—who the Sabrina the Teenage Witch actress shares with husband Mark Wilkerson—headed off to school on Aug. 7.

She got the boy to his class! The singer was on hand to watch her and ex Mike Caussin's son Jace start kindergarten on Aug. 9.

Meanwhile, the former couple's daughter Jolie began third grade.

The Bachelor Nation star's daughters Kinsley and Charlie started the seventh and fifth grade, respectively.

"I just can’t believe how grown up they are," she wrote on Instagram Aug. 22, "& that they still love to match…& that I still cry on the first day of school no matter how long I’ve been doing this."