Carrie Underwood was the baby of the family. Her teenage sisters had her sing one surprising song at age 3.

Carrie Underwood is one of the biggest stars in country music. She won “American Idol” back in 2005 and never looked back, selling out arenas and gathering awards ever since.

Long before any of that, she was just the youngest Underwood girl in Checotah, Oklahoma. She was born in 1983, the baby of three sisters. Her dad Stephen worked at the local paper mill. Her mom Carole taught at the elementary school for 25 years, and both of Carrie’s older sisters, Shanna and Stephanie, grew up to be teachers too.

Here’s the part that shaped her. Those two sisters were teenagers while Carrie was still a toddler. So she wasn’t really a little sister so much as a tiny live-in audience, tagging along behind two girls who were almost grown.

The sisters ran the radio in the house, and that’s how Carrie first fell in love with music. “They controlled the radio when I was 5 years old,” she said in an interview with Apple Music Country. What they played wasn’t what you’d expect from a future country queen. They leaned hard into rock, and Carrie soaked up all of it. For a girl who would one day rule country radio, that’s a pretty funny place to start.

Her mom has said the house emptied out early. “Shanna was already gone from the house and Stephanie went to college,” Carole once explained, so Carrie spent a good chunk of her childhood almost like an only child.

But those early years with her sisters left a mark she still laughs about today.

So what was the song the big girls taught their 3-year-old sister to belt out? It was “Smokin’ in the Boys’ Room,” a rowdy old rock tune that’s about the last thing you’d picture coming out of a tiny Oklahoma toddler. The sisters thought it was hilarious, and little Carrie went right along with it. She was barely out of diapers and already had a signature number.

“They thought it was funny for me to sing, like, ‘Smokin’ in the Boys’ Room’ as a 3-year-old, so I did,” Carrie said.

And the singing was only part of the job. Whenever the older girls had friends over, Carrie was the whole floor show. “And I was entertainment. I was dance monkey. I was dance monkey for their friends,” she said.

She owns that rock-loving streak completely now. “I feel like at this point, all my fans know I have a huge love of rock music,” she said. Those same sisters were sitting front and center the night she won “American Idol” in 2005, watching their little dance monkey turn into a star.

The photos here show Carrie with her mom and her two sisters over the years.