May 1 my Maxi Drew turned 3.... I am in complete denial

A photo posted by Jessica Simpson (@jessicasimpson) on May 4, 2015 at 1:20am PDT

Mama’s gorgeous girl! Jessica Simpson is not ready for her firstborn daughter, Maxwell Drew, to grow up. But the fashion designer’s baby girl is a baby no more! 

“May 1 my Maxi Drew turned 3.... I am in complete denial,” Simpson, 34, captioned a black and white Instagram shot with the blonde cutie. 

Maxwell, who is the frequent subject of her mom’s social media posts, has her serious model face on and is wearing a blinged-out necklace. The little fashionista also wore a top with giant flowers and her long locks up. 

Her proud (and slim!) mama grinned while hugging her little girl. 

Simpson wasn’t the only one celebrating Maxwell’s big day. On Sunday, May 3, her uncle Evan Ross Instagrammed a shot wearing a pirate’s hat via Instagram, writing, “I was fully plugged in at my sister in laws @jessicasimpson baby girls birthday today #maxwell... They went all out!!!!”

Prior to her party, Maxwell was treated to the ultimate shopping spree at Toys “R” Us with her parents, two nannies, and grandmother Tina Simpson

“They spent a long time in the store going up and down every aisle,” an eyewitness told Us Weekly. “Maxwell was so excited. She picked out a coloring book about birthdays and a huge pink stuffed bear. Jessica and Eric [Johnson] filled up two shopping carts with toys and games for Maxwell and Ace. They got them each plastic baseball bats, Minion toys, a giant Spider-Man, several books, and arts and crafts."