Rebecca Black is running a few minutes late to rehearsal but no worries – her band is already warmed up, and the drummer needs a break to find someone at the West Hollywood rehearsal studio to fix the busted head on his kick drum.

While he waits behind his kit most of the other musicians lounge on a beat-up black leather sofa, checking out the comments on the YouTube video posted the day before by their 15-year-old leader, in which she introduced the players who’ll accompany her when she makes her live headlining debut at the House of Blues in Anaheim on Sunday.

It’s kind of a weird thing to get your head around: Rebecca Black, the Orange County teenager whose song “Friday” was the biggest viral video of 2011 is only now, nearly two years later, playing her first full show?

Even Black sees how her trajectory doesn’t exactly follow the norm for overnight sensations, and admits it wasn’t always easy to stick to the well-considered career path she and her advisors have followed.

“It definitely was hard a lot of the time,” she later says of the methodical way her post-“Friday” career has unfolded. “It’s so easy – we could have just recorded a bunch of songs really fast and just put them out there while ‘Friday’ was ‘the thing.’ And yeah, they would have gotten a lot of attention. So it was hard.

“But everyone told me, ‘It’s OK, you can wait.’ And I’m so glad I waited. It’s a hard thing to understand when you’re young, and being that I’m impatient, too.

“But it’s so worth it to take your time.”

Black arrives, the drum head is replaced and the rehearsal begins with a full run-through of the 12-song set she’s prepared for the House of Blues show. And yes, the set includes “Friday,” but like so much else about Rebecca since she and the song and the video splashed onto the scene, it is different now, growing up, you might say, like the girl who sings it.

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“Friday” might easily have been both the beginning and the end of Rebecca Black.

Sure, the song that taught us which day falls between Thursday and Saturday, and posed the eternal question – kickin’ in the front seat, or sittin’ in the back seat? – made Rebecca’s name the biggest search of the year on Google’s Zeitgeist list in 2011.

But a lot of the attention she and “Friday” got was, to put it mildly, not nice. Not nice at all. So try to imagine being a 13-year-old kid in the eighth grade that is suddenly the laughingstock of a good part of the Internet. Your feelings would certainly be hurt by all of the haters, especially since you believed the song they were mocking wasn’t even the best representation of what you could do.

“You have moments when you want to show everyone what you’ve done,” Black says. “Especially at a time when you’ve got so many critics, being 13 you want to show everyone who’s been rude to you about ‘Friday.'”

But her manager, Debra Baum, counseled her to take it slowly. To pick the best songs and make the best singles she could. And wait until she got firmly on her feet as an artist before walking out into the spotlight on stage.

“Everyone started sending me songs,” Black says. “There were hundreds of songs being sent to Deb.”

Rebecca picked her eight favorites out of all the ones Baum screened for her and in 2011 started recording the first of them with producer Charlton Pettus, the guitar player for Tears for Fears, another group Baum had managed in the past. At the time, they were working to create pop songs like the catchy confections of Rebecca’s favorite artists.

“Being 13 and going into the business, everyone wants to be the next Katy Perry or Lady Gaga,” she says. “That was kind of the whole direction I wanted to go. But then I discovered that it’s really more acoustic for me.”

Driving home to Orange County with Baum one day earlier this year, Rebecca says she had an epiphany.

“Maybe the direction I wanted to go in isn’t super poppy,” she says she remembers thinking. “So I brought it up. And it turned out that she’d been thinking that too and was going to bring it up to me.

“The first song that I heard where I went, ‘Yes, this is it,’ was ‘In Your Words.’ I was, ‘Yes, this is it, I want to record this now.'”

As for how she sees her new style and sound?

“It’s much more acoustic,” she says. “My manager likes to use a term, which is a pretty good analogy, that it’s Taylor Swift without the twang. It’s a much more mature sound than ‘Friday.’ It’s more authentic, more organic.”

In the rehearsal room, as Black and the band work through the set, her new sound is easy to hear. The vocals are left in their natural state, not processed as on “Friday.” The band, led by guitarist Brennan Meeks, rocks appropriately hard on the upbeat numbers, with acoustic guitar and harmony vocals on slower tunes adding to that singer-songwriter aesthetic that Black says she’s into now.

Midway through the set she and guitarist Cole Citrenbaum, himself just 17 years old, take seats on stools while the rest of the band takes a break. They play two songs with just Cole’s acoustic and vocals to supplement Rebecca’s voice – a cover of Ed Sheeran’s “A Team” and her own “Take Me Away.” And in that unplugged mini-set they sound perfectly lovely.

“It’s so cool!” Rebecca says of working with the band with which she’ll have had just two weeks of rehearsals before the House of Blues gig. “That was my top priority for the show, to have a band. (Her only other concert experience, a festival in New Jersey in August, featured her live vocals to the accompaniment of backing tracks.)

“Luckily everyone in my band is so kind-hearted and nice, and so funny and warm,” she says. “They were all just welcoming and outgoing. I think I’m really lucky. Everyone in the band is so crazy talented.”

Was she worried how her band mates might treat given the popular notoriety of “Friday,” we wondered?

“They were really great about it,” she says, laughing about the way that song forever will be linked to her. “I don’t have a problem with it. I think it’s really hilarious when one of my own friends cracks a joke about it. Even I do sometimes: ‘Oh, which seat should I take?'”

It was tough, she admits, dealing with all of the negative comments when that song made its first big splash. But that’s helped prepare her to be judged by listeners now. While she hopes and believes they’ll like the new material and live performance a lot, if some don’t, so be it.

“I think obviously not everyone is going to like what I present,” Rebecca says. “Obviously I want them to be less and less critics (or) haters. But it’s also reassuring that I do have supporters from the other songs I’ve done, too.

“There are definitely people who are coming to the show just to see how I do,” she says. “I’m really comfortable with me.”

Rebecca Black

When: 6 p.m. Sunday

Where: House of Blues, Anaheim

How much: $17.50 plus fees

For more: ticketmaster.com or rebeccablackonline.com

You’ll find videos for all of them at rebeccablackonline.com.

Contact the writer: 714-796-7787 or plarsen@ocregister.com