Bothell’s star actress appears to be an adult residing inside a 13-year-old’s body.

Keaton Whittaker has taken on this role for the last three months and is living big in New York City and maturing with each line delivered and verse sung on the Broadway stage.

She started rehearsals alongside seasoned actresses Angela Lansbury and Catherine Zeta-Jones in late October for the revival of Stephen Sondheim’s “A Little Night Music.” Previews began Nov. 24 at the Walter Kerr Theatre in New York City and opening night was Dec. 13.

And forget about a New York minute. More like months, since Keaton is under contract for “Night Music” through the end of May, early June, right before the Tony Awards ceremony.

“She’s got a lot on her plate and she’s handling it remarkably well. A 13-year-old kid navigating in New York City, that’s what I notice the most,” said mom Nancy over the phone from the Big Apple Tuesday. “She has to be responsible to do her schoolwork online, put the computer away, put her backpack on and go to work. It’s not a typical schedule.”

Nancy joked that some adults would be overwhelmed by Keaton’s eight-show-a-week docket.

“It’s so great, I’m so happy to be here. I’m just along for the ride,” said Keaton from her mid-town Manhattan apartment, which she shares with her mom and 10-year-old brother, Chase. “Oh my gosh, the cast is so lovely … they’re talented, such nice people.”

Lansbury (Madame Armfeldt) and Zeta-Jones (Desiree Armfeldt) have been invaluable role models for Keaton (Fredrika Armfeldt), said the young thespian, who enjoys shopping with friends when she’s not on stage or studying.

“I’ve learned a lot from them: Their reactions and how they’re always tuned into their characters,” said Keaton, who recorded the “Night Music” CD with the cast this week. “(On opening night) I was nervous, but I just did some deep breathing and was just confident in the fact that I know what I’m doing and I’ve rehearsed.”

Nancy and Keaton credit the folks at Seattle-area The 5th Avenue Theatre, Village Theatre and Seattle Musical Theatre for getting her up on stage in a host of productions, including “White Christmas” and “Into the Woods.”

“They prepared her really well. She’s learned professionalism, how to behave and what to expect,” said Nancy, a stay-at-home mom whose husband, Clay, works for Technogym in Seattle.

Nancy noted that Keaton’s climb to Broadway has been a whirlwind. One day, she was auditioning just for the experience, and the next day, Nancy was apartment hunting.

And mom has certainly been caught up in the bright-lights, big-star aspect of the whole deal.

“It’s pretty awesome,” she said. “There’s a picture of Catherine Zeta-Jones and Angela Lansbury with Keaton standing next to them … that’s pretty weird.”

After Broadway, the sky’s the limit, says Keaton.

“I’m always open to doing more, challenging myself,” she said. “I’d love to do roles here in New York, maybe get into film at some point. I want to do what I love, which is singing, dancing and acting.”