(CNN) -- Actress Anna Kendrick's days are now full of life-changing moments. She's quickly becoming famous.
"It's so strange because it only ever comes in these small bursts," she said. "Like all of a sudden I'm on the red carpet for a premiere and it's louder than anything should ever be. Or a bunch of people will take my picture at an airport without asking my permission. It feels like a double life, where I do all these strange things and then I go back to my apartment and my friends -- nothing feels different."
CNN spoke to the 24-year-old actress -- who is already receiving Oscar buzz for her supporting role in the new film "Up in the Air" -- the morning after another of these pivotal moments, her first talk-show appearance on "Late Night with David Letterman."
"I don't think I've ever been so nervous in my life," Kendrick said of Letterman. "I was literally shaking like a Chihuahua backstage."
Kendrick, who also plays Jessica Stanley in the phenomenally successful "Twilight" films, grew up in Portland, Maine, where she was bitten by the acting bug at age 10. Soon her parents were taking her to auditions in New York.
"One of them would usually drive me, and then one of them would go on the bus with me. And then after a while they couldn't take off work all the time, so they decided to try letting my brother take me."
So at age 11, Anna and her then-13-year-old brother, actor Michael Cooke Kendrick, started taking the seven-hour Greyhound bus trips alone, staying in hotels when they arrived.
"We used to make sure we got the back row, where there's three seats, and we'd just spread out like a couple of orphans and people would leave us alone. But there were definitely some sketchy characters at night when we would be at the bottom of the Port Authority [bus terminal] waiting for the bus from New York to Boston."
Within a year the actress landed her first role, as Dinah in the Broadway musical "High Society." Her performance earned her a Tony nomination, making her the third-youngest nominee ever. After a number of other high-profile theater productions, Kendrick made an easy transition into film with 2003's musical comedy "Camp."
But the role that paved the way for her success was in the 2007 indie darling "Rocket Science," in which Kendrick played the prickly and precocious high-school debate champ Ginny Ryerson.
Her performance in the film was praised by critics and landed her in the crosshairs of director Jason Reitman ("Juno" and "Thank You for Smoking"), who says he wrote the part of Natalie Keener in "Up" specifically for Kendrick.
Facing the nonstop media blitz of a young star on the rise, Kendrick says she now identifies more than ever with her character in "Up," who's a reluctant frequent flyer.
"I definitely feel like Natalie in the sense that I'm uncomfortable in airports, but they are starting to feel more like home. I'm at [an airport] right now."
But after working alongside sudden megastar teens like Robert Pattinson and Kristen Stewart, Kendrick is a bit leery about the spotlight growing too bright.
"It totally terrifies me. I think that losing your anonymity is one of the scariest things in the world. But I guess I've been allowing myself to think about it for a long time, because it's the kind of thing you want to be emotionally prepared for."
Her co-star in "Up in the Air," veteran actor George Clooney, has been a positive model for what Kendrick calls living a successful "double life."
"I think he just constantly reminds himself of where he came from and how lucky he is and how quickly it could all go away."
But the buzz around Kendrick isn't likely to go away any time soon. She just finished filming the highly anticipated "Scott Pilgrim Vs. The World," starring Michael Cera, due out next year.
"Up in the Air" is in select theaters now and opens nationwide on December 25.