Jennifer Lopez is celebrating her kids’ latest milestone.

The “All I Have” singer shared a heartfelt letter to her twins Max and Emme—whom she shares with ex-husband Marc Anthony—in honor of the pair’s 18th birthday, reflecting on how motherhood transformed her life for the better.

“When I would hold you as infants, I honestly felt as if I were holding two angels sent straight from heaven above,” she wrote in a post on Instagram Feb. 22 alongside a video featuring highlights from the twins’ childhood. “My life was changed forever. I cannot believe you are now adults…18 years old!”

Describing Max and Emme as “kind-hearted, generous and loving,” the 56-year-old detailed her close bond with the teens.

“It has always been the three of us,” she continued. “We have been on this journey together. We have always had each other to hold on to and be that steady presence in the middle of any snowstorm. And I promise you, my beautiful coconuts, no matter how big you get, that’s how it will always be.”