LeAnn Rimes on Turning 40: 'I Wouldn't Be 22 Again If You Paid Me' 

LeAnn Rimes isn't letting a milestone birthday pass her by.

"We have three celebrations planned," says the Grammy-winning artist, who turns 40 on Sunday. "I'm at that point where I'm seriously ready. I'm over my thirties. Let's get to 40!"

In fact, in recent months Rimes — whose upcoming album, god's work, is out Sept. 16 — has done plenty of self-reflection.

"As a child, I remember thinking 40 was so old," says Rimes, who rose to global fame at just 13 with her chart-topping rendition of "Blue." "But now that I'm there, I feel like I have so much life under my belt. I'm much wiser. I wouldn't be 22 again if you paid me!"

The singer says she's also prioritized her health and wellness of late.

"About six months ago, I started really focusing on taking care of myself," says Rimes, who counts breath work and meditation as part of her self-care routine. "A big part of my life has been overriding my body because I've had to show up and be on all the time. I've had to care about what people think of me for so long. So not abandoning myself and what I need has been a big shift."

And Rimes says her marriage to Eddie Cibrian, to whom she's been wed since 2011, has also been personally impactful.

"We have taught each other a lot," says the singer. "I appreciate us getting older together as adults who are growing and shifting. And Eddie has never been afraid of my evolution."

When it comes to lifestyle changes, Rimes says a simple one has provided much relief.

"For the most part, I've completely ditched high heels," she says with a laugh. "Why did we do that to ourselves?"

For more from LeAnn Rimes, pick up the latest issue of PEOPLE, on newsstands everywhere now.