A few minutes past 7 o'clock, LeAnn Rimes marches onstage and the innocent deception begins.

She's a picture-perfect model in skin-tight black Wranglers. Not a blond hair out of place. Not a blemish in sight. Her bright white, flawless smile dazzles.And when she sings, watch out. Her smooth voice lilts between seductive siren and country-rocking temptress.

She's deceptive only because a 13-year-old isn't supposed to look - or sound - anything like this.

"Really, though, what is 13?" LeAnn asks before the first of two sold-out shows at the Land of Oz nightclub. "Age really is just kind of a number. It doesn't determine a lot, I don't think. This is just me."

Well, "just me" is making the country music world spin. LeAnn's just-released first national album, "Blue," debuted on the Billboard country charts at No. 1, perhaps the biggest debut by a new country artist ever. The album sold 124,000 copies its first week. It also leaped into the No. 4 spot of the Billboard 200, a ranking of all albums nationwide; this week it moved up to No. 3.

It's her first single that's sparking all the fuss. The song, also called "Blue," was written more than 30 years ago for Patsy Cline, who died before ever recording it.

LeAnn's version scored big on American radio and now is nearing the top of the charts in Canada and Australia.

Close your eyes when you hear the song and it's almost as if Cline were back. But on the record and onstage, LeAnn tries not to impersonate Cline but rather honor her.

"It's neat to be compared to her," LeAnn says. "She's the first person I ever really listened to singing. She's definitely one of my idols. But I also want people to know I can sing other things besides Patsy Cline stuff. I want everyone to know me for me."

So during her 14-song set she sings nearly all of the tracks from her album (including one she co-wrote) and a few cover tunes like "Stand By Me" and the Dolly Parton-written, Whitney Houston hit-making "I Will Always Love You."

LeAnn sings just two Cline numbers. She ventures into "Leavin' On Your Mind" midway through the set and saves "Crazy" for the sole encore.

During the show LeAnn lacks the onstage polish her singing voice would lead you to expect. Her banter between songs is limited and a bit contrived. Despite performing since she was 5, LeAnn doesn't yet seem totally comfortable in the concert setting.

Then again, she is only 13.

"When I was 13 I didn't know up from down let alone anything she's got to know," says Ted Cramer, program director for country radio station WDAF-AM, who helped bring LeAnn to Kansas City. "The first time I saw her it just blew me away. I couldn't believe where that voice was coming from. She's going to be a phenomenal act. This is a once-in-a-lifetime kind of performer."

Even her band members, most of whom have been playing with LeAnn for the past two years, are still amazed by her.

"She's scary - in a good way," drummer Fred Gleber says. "Traveling with her I get to see the 13-year-old. But when it comes to music, she knows what she wants. She's savvy."

And if the band musicians had any reservations about playing with a teenager, they're gone now.

"When I heard her sing, her age didn't matter," bass player Curtis Randall says.

With the sudden success and flurry of media attention (she's been a USA Today cover story and a feature in Time), one might expect a bit of a young brat to emerge.

Not so, says anyone who knows her.

"She's proud of what she's done," says LeAnn's father and co-manager, Wilbur Rimes. "But it's not a spoiled kind of proud."

LeAnn's parents, whose full-time attention is focused on their daughter's career, work hard at not letting the 13-year-old slip away.

"You've got to try to balance it all," Belinda Rimes says from her daughter's tour bus. "There's a lot for all of us to learn."

Much of LeAnn's time is spent now on business. She flew into Kansas City after days of taping a television commercial in Los Angeles. And she headed out on her bus after her second show here for a gig in Wisconsin.

Like most teenagers, LeAnn gives her parents a little credit for her staying grounded, but "I pretty much figured it out on my own."

"I've seen so many people get kind of a big head and think they're better than everybody else," LeAnn says. "I don't think I'm better than anyone who's buying a ticket. Everybody has a different talent. A lot of people out there have talents that I don't.

"So as long as I keep that thought, I think I'll be OK and not get the big head kind of thing."