The singer shares sons Kingston, 14, Zuma, 11½, and Apollo, 6, with ex-husband Gavin Rossdale

Gwen Stefani feels blessed for her children.

On Tuesday, the "Nobody But You" singer, 50, marked her eldest son Kingston's 14th birthday with a heartfelt Instagram post. Sharing a sunny beachside photo of her child, Stefani wrote that she's grateful to be his mother.

"Happy 14th bday to my first born son thank u God for making me his mamma 🙏🏻gx," she captioned the post.

Kingston is the oldest of three boys for Stefani, who also shares sons Zuma, 11½, and Apollo, 6, with ex-husband Gavin Rossdale.

The Grammy winner welcomed Kingston James McGregor on May 26, 2006. At the time of his birth, he weighed 7½ lbs.

A few years into motherhood, Stefani said Kingston was "the most amazing thing that's ever happened to me."

"It's the best thing that's ever happened to me in my entire life. He is just … a miracle," she added at the time. "The whole thing … in the stomach, coming out, and then they're … a human. It's just weird; it's incredible."

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In October, Stefani opened up about what she has learned from being a parent to three boys.

"One thing the kids have taught me is how to be more organized," she told Shape magazine at the time.

"I lived at home until I was 26, then I had a tour manager, then a manager, then an assistant," Stefani explained. "On tour, you even have somebody who has the key to your hotel room. But as a mom, you have to be the one in charge."

Gwen Stefani (L) and Kingston Rossdale
Gwen Stefani with Kingston in March 2017
| Credit: Chris Polk/KCA2017/Getty

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The star also told the magazine that balancing her career, parenting and her relationship with Blake Shelton is challenging but vital.

"Balance is the hardest thing, but it's also the most important — being with my family, having time with Blake where we just watch movies," said Stefani. "It seems like, with your career, you have to keep swimming, keep moving, or else you're going to look back and go, 'Shoot, it's over.' I don't like feeling like that."

She added: "I want to do creative things when I want, and I want to stop chasing all the time. It's hard, but I'm really enjoying being in the moment."