"I can't believe she's 4 already," Brittany, 29, gushed via Instagram Stories on Saturday, February 22, sharing snaps from the Bluey-themed party she hosted based on the popular animated children's series.

To celebrate Sterling's big day, the party venue was decked out in themed merch and colorful balloons.

Sterling is the firstborn daughter of Brittany and Kansas City Chiefs quarterback Patrick, 29. (They also share younger children Bronze, 2, and Golden, 1 month.)

"This sweetest, most kind little girl ever! I thank God every day for choosing me to be your mom, you have taught me so much about life and what matters most and I truly am so thankful you made me a mama," Brittany wrote via Instagram on Thursday, February 20. "You are the best big sister to Golden & Bronze and they are so lucky to have you guiding them your Mom and Dad love you beyond and more."

Keep scrolling for a peek into Sterling's adorable birthday bash: