With Sunday’s opening of Jason Robert Brown’s new musical, “13,” Broadway finds out what it’s like to be a newly minted teenager in 2008.

Directed by Jeremy Sams (“Noises Off”), “13” is about Evan Goldman, whose parents’ divorce uproots him from Manhattan and transplants him in Indiana, just in time for his bar mitzvah. He has to navigate a new school with all its cliques, hierarchies and rumors.

There’s not a single adult in the cast and one unseen adult (musical director and conductor Tom Kitt, from Armonk) in the pit.

The musical has its share of talent from the Lower Hudson Valley: Besides Kitt, the composer of “High Fidelity” and “Next to Normal,” the cast includes Delaney Moro (a Pomona native, now of Nanuet). Zach Page, of Montebello, plays guitar in the all-teen band.

Moro, a Broadway veteran at 13, created the role of Jane Banks in “Mary Poppins.” She doesn’t want people to confuse “13,” with “Thirteen,” the R-rated 2003 film starring Evan Rachel Wood as a girl who chooses to fit in with the popular crowd by going with the flow, leading to sex, drugs and crime.

“I just saw it on Monday and it’s totally disturbing,” Moro says.

“It’s an upsetting movie,” interjects the 15-year-old Page.

Nor is “13” “High School Musical,” says Moro, who speaks in long sentences without taking a breath.

“It’s right in between ‘Spring Awakening’ and ‘High School Musical,’ which is good,” Moro says. “It’s got some humor that kids wouldn’t get that only adults get, but it can relate to kids easily. It’s a teen-adult show, which is good, because it’s not a kiddie show and only for kids. There are a lot of things that adults can relate to and that kids can relate to, on account of we’re kids playing it.”

To reinforce that teens-playing-for-teens theme, Kitt plays the keyboard and conducts the show from behind a flat; only the five teen-band members can be seen.

Getting to tonight’s opening meant surviving a competitive audition process.

At her second audition, Moro was asked to tell a joke.

“I can’t even remember what it was, but I thought of a really random one,” she recalls. It must have been a good joke; Moro got a third audition.

“I was the only girl who sang at the end of the third audition,” she says, “and it was really cool, because it was just me and Jason and Jeremy. And Jason was just like, ‘Just imagine that nobody’s here. We’re going to sing together. You’ll sing and I’ll sing and we’ll just have some fun. He made me feel really comfortable. It wasn’t like a really scary audition.

“Jason was like, ‘Pop a squat. Let’s have some coffee!’ And I was like, ‘You’re Jason Robert Brown!” she squeals.

The band audition, Page says, was one full day – from 9 a.m. to 6:30 p.m. – “so many kid musicians, more than I’ve ever seen in one place.”

“We were all in the same room for the whole time and at a table was Jason Robert Brown and Tom Kitt,” Page says. An excerpt of the show’s title song had been e-mailed to Page and the other hopeful musicians and they had an MP3 to study.

“Tons of kids in one room: We got all the guitar players here, drummers over there, keyboard players there and bass players on the side,” says Page, who plays acoustic and electric guitar on “13.”

“They just put together bands – ‘You stay, switch you out, try this drummer, switch drummers’ – until they heard what they wanted. It was a real band atmosphere, which is the way to do it, because you have to see how they play together.”

Kitt says that room held about 75 kids, but he only needed six. (One extra player covers for the others.)

“This band is phenomenal,” he says. “They are mature beyond their years as musicians. It’s been one of the most enjoyable experiences I’ve had in the theater, playing with this band.”

Moro has known Page since they were in preschool together in Ramapo. (“When we were like fetuses,” she says.)

The Moros recently moved from Pomona to Nanuet; Page, whose family name is Goldstein, still lives in Montebello. (He took his maternal grandmother’s maiden name, Page, as his stage name.)

Moro has acted with the Goldsteins before, too, at Random Farms Kids Theater and at the first kids production at Westchester Broadway Theatre, when John Fanelli cast Moro as little Eponine, Zach as Gavroche and Zach’s older brother, Josh, as Marius.

Page has done “the acting, singing musical theater thing, starting out in youth theater and actually had a good run,” he says.

In “A Christmas Carol” at Madison Square Garden – with Jim Dale as Scrooge – Zach played Scrooge at 8 and “13” star Graham Phillips (who plays Evan) played Tiny Tim.

Page is relatively new to the musician side of the business, having picked up the guitar for the first time four years ago. He toured for three summers with the Paul Green School of Rock All-Stars.

“Paul Green gave me the most amazing performance experiences I’ve had so far in my life,” playing Europe, including at the Zappanale Festival “in front of thousands of insane Frank Zappa fans in Germany.”

“It was an all-Zappa set, which is pretty hard stuff to play,” he says. “We also played Led Zeppelin and Black Sabbath at night and played till three in the morning. We were exhausted.”

His Broadway hours will be more civilized. He’ll still have to fit in his course work at Barnstable Academy in Oakland, N.J., where he’s a sophomore. Page says the school’s administration has made Broadway a reality.

“They’ve been so flexible,” he says. “They’ve been great.”

Jason Robert Brown’s rock score is an education in itself, Page says.

“The first rehearsal – I’m not the best reader – they put the music in front of me and everyone else is reading and ‘1, 2, 3, 4 …’ It’s definitely put my music reading on a new level, which is good for me” he says.

Kitt likes what he’s seeing and hearing.

“What Delaney did in the auditions and what she continues to do every night is to make people invest in her and make the most of the material she’s got. And she’s delightful to work with,” he says.

Moro plays Kendra, a tall, beautiful girl who is the object of affection for most of the boys in the school.

“She’s very optimistic. She’s always thinking of the upside of things. And she’s extremely dumb and ditsy,” Moro says

Is that fun to play?

“It’s me on stage!” she says without a moment’s hesitation. “The blonde never lies.”

Moro says she subscribes to Kendra’s credo: “Malls are mini miracles.” “If I’m not home, I’m at the Palisades Center,” she says.

There’s little time for the mall these days. She has been handling her school work from Saddle River Day School with a tutor and will return to the campus after the opening-night hoopla has passed.

“I’m just performing and school. Nothing outside of those two things,” she says.

Page, Kitt says, is “like everyone in this band. It feels like he was born with it. It’s so much fun to have these kids constantly make you roll your eyes in disbelief. He’s an incredible musician and an intelligent player.”

If “13” brings the audience back to that age, the rehearsals have had the same effect on Kitt, who lived in Port Washington on Long Island when he was a new teen. (His family later moved to Armonk.)

“Thirteen was one of the hardest years of my life, in all seriousness. I had a terrible time when I was 13,” he says. “It was a really awkward year for me. So when I first walked into rehearsal, I kind of had a moment of ‘I can’t believe I’m back facing this age.’

“But think about it: It’s awkward. Your voice is changing, your hormones, you don’t know who you are, what you are. And there was all this peer pressure going on, this cliquiness going, and you’re just trying to get through it. And I had a bar mitzvah that year, so I have a lot in common with Evan, in that I was just trying to survive it.

“What’s wonderful about this show is that we don’t see the party, we see the Haftarah. We see Evan chant. What you realize, building up to your bar mitzvah – you think ‘party, party’ and fun – but it’s actually the service that means the most.”

‘13’
Where: Bernard B. Jacobs Theatre, 242 W. 45th St.
When: Opens tonight.
Tickets: $76.50 to $111.50.
Call: 212-239-6200.
Web: www.13themusical.com
Video: Check out the show’s title song at www.13themusical.com/videos/

Photo by Carucha L. Meuse/ The Journal News: Musical director Tom Kitt of Armonk, actress Delaney Moro of Nanuet and band member Zach Page of Suffern of the new musical “13,” outside the Bernard B. Jacobs Theater in Manhattan.