It’s hard to believe Jessica Simpson’s daughter Maxwell is already 5 years old! The Dukes of Hazzard star took to Instagram on Monday to wish her baby girl a happy birthday with a family photo from Maxwell’s mermaid-themed birthday party.

“My baby Maxwell is 5 years old today. She makes everyone’s life mermaid magical,” she wrote alongside this fierce photo where the mother-daughter duo shows off their best poses. “Happy Birthday to our fairytale princess. Mommy, Daddy, and Ace love you with our ‘holy hearts’ (as Max would say),” she wrote, adding “can you be 5 forever.”

Clearly, Maxwell has a mermaid obsession, as she chose an adorable sparkly mermaid skirt and waterfall braid as her birthday outfit. Meanwhile, mom looked fierce in a plunging white minidress and platform peep-toe pumps. Husband Eric Johnson smiles in a white button-down, while their 3-year-old son Ace looks adorable in a printed tank, bathing suit shorts, and sneakers.

Simpson also shared a throwback to Maxwell’s birth, when the baby girl made her “first splash.”

Happy birthday, Max!