How Amanda Shires' 4-Year-Old Daughter Mercy Inspired Her to Start Country Supergroup The Highwomen

When Amanda Shires’ daughter Mercy, who turned 4 on Sunday, began to show interest in music, the singer-songwriter started worrying.

“That’s scary enough as a mom, or as anybody in music — it’s not an easy business,” she tells PEOPLE. “And I thought, Well, what’s the worst that can happen? And I was looking at the charts and I was like, Well, the worst that could happen is that she’d have to fight really hard in country music.”

Shires, 37, decided she’d do something: start a band. Her producer recommended she reach out to Americana singer Brandi Carlile. She joined, and so did country-pop star Maren Morris. Later in the studio, the trio invited one of their songwriters, Natalie Hemby, to get on the mic and solidify The Highwomen‘s lineup.

Shires has praise for each of her bandmates. Morris “uses her platform for good, and it’s incredible”; Carlile “could sing the phone book and it’d be a hit”; Hemby “just brings a bunch of wisdom and empathy and heart.” Working as a group, she adds, is effortless.

“The music just fell into place. We even found our own parts naturally, our voices kind of knew where to land,” Shires says. “I’m not a big hippie, but sometimes when things happen that easily, it seems like it’s meant to be.”

Their group is an answer to ’70s supergroup the Highwaymen, which featured Johnny Cash, Willie Nelson, Kris Kristofferson and Waylon Jennings. Shires’ quartet revamped the group’s self-titled song, working with one of the original songwriters to adapt the lyrics for women’s experiences — which she wanted to spotlight. They released a self-titled album of 11 more songs in the same vein on Friday.

“I’m not hating on country music,” Shires insists. “We see a couple of doors that have closed, and we just want to crack them open a little bit. I mean, you get your stories from your mothers, why can’t you hear some from a singing lady?”

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It’s not just about gender in country music, either. One of the songs on the album, “If She Ever Leaves Me,” tells a love story with a woman narrated by Carlile (an out lesbian). Shires and her husband, singer-songwriter Jason Isbell, wrote it for the singer. “Brandi says that I’m part gay,” she jokes. “That might be true, I really do think she’s quite beautiful.”

In seriousness, Shires adds, “Surely it’s necessary to have songs about whoever you love.”

And Isbell, who she married in 2013 and plays guitar on some of the album’s tracks, has always valued and supported her career since Shires joined his band The 400 Unit in 2009. “In my eyes, he looks stronger because he’s not afraid to work with women and to be emasculated on occasion,” she says.

The Highwomen performed with country icons Dolly Parton and Sheryl Crow when they made their debut at the Newport Folk Festival in July, but now, Shires wants to get more people involved: from Bonnie Raitt to Stevie Nicks to Cardi B.

At the end of the day, though, it’s not about the stars. Says Shires, “Everybody that’s a woman working in their field or a woman raising kids or a woman with a nanny and a mom helping out, and good feminist guys, and husbands like mine, and band members that support women — all these people are highwomen.”

The Highwomen is available now.