By Lisa Ingrassia and Michael Y. Park

Tuesday November 17, 2009 10:50 AM EST

Kristen Stewart

Eric Charbonneau/WireImage

Talk Isn't Cheap For Kristen Stewart | Kristen Stewart

She’s one of the biggest actresses in the world right now, but Kristen Stewart says she’s still the same old girl she was before she and the Twilight vampires took a bite out of Hollywood.

And nowhere was that more evident than at the Los Angeles premiere of New Moon Monday night, where she and costar and pal (and silver-screen werewolf) Taylor Lautner opened up about their biggest fame anxieties.

“We both had to do talk shows, and we were really nervous about it,” Stewart, 19, told PEOPLE on the red carpet. “And we both nailed it, so I was like, ‘Congratulations.’ ”

So why pursue a movie career if life in the spotlight gives her butterflies in the stomach?

“It’s a little weird, but it’s all because of this …. The focus for us is the focus that [the fans] have, which is the movies,” she said. “This is what you work for. Not the attention, but the fact that you can have a common interest.”

That’s typical Stewart, said costar Anna Kendrick, who plays vampire-loving Bella Swan’s human classmate Jessica.

“She certainly hasn’t gone and changed on us,” Kendrick said. “She’s the coolest chick you could ever hope to meet. She’s so down to earth, and such a pro.”

And, yes, you can’t expect an unbiased opinion from a woman’s dad, but Stewart’s onscreen father still insists on singing her praises.

“She doesn’t get cluttered up with all this stuff that goes on,” Billy Burke said. “And I admire that about her. She’s going to be around for a long time. I’m always impressed by her.”

PeopleTV: The Stars Come Out for the New Moon Premiere