The Canadian actress may not look like it but she sure sounds like it. Even though she turns 21 next week, she speaks as if she is pushing 30, revealing a remarkable level of knowingness beyond her years.
In a way, she is not too different from the eponymous spunky character she plays in Juno, the new movie by Jason Reitman (Thank You For Smoking, 2006), which chronicles a pregnant teenager's bittersweet journey into adulthood as she struggles to find suitable adoptive parents (Jason Bateman and Jennifer Garner) for her baby.
The movie, which opens here tomorrow, is up for four Academy Awards later this month - Best Picture, Best Director, Best Original Screenplay and Best Actress for Page.
Speaking on the phone from Los Angeles, she is affable but reticent. When asked about Oscar prospects, she gives guarded replies.
'I don't really like the competitive side of things,' she admits. Deep inside, she knows she does not stand a chance beating veterans Cate Blanchett (Elizabeth: The Golden Age), Julie Christie (Away From Her), Laura Linney (The Savages) and Marion Cotillard (La Vie En Rose).
Cotillard was just named Best Leading Actress by the British Academy Film Awards on Monday.
'I'm a huge fan of all the women nominated. They have all given incredible performances and it feels insane just to be acknowledged alongside them,' she says.
Has she got her acceptance speech prepared then, just in case?
'No, that's really not how my brain works,' she says, with a chuckle.
Even if she does not win, she will still retain a spot in the Oscar annals - as the fourth youngest woman to be nominated for Best Actress.
The first three were Keira Knightley (who was 20 years and 11 months when she was nominated for 2005's Pride & Prejudice), Isabella Adjani (20 years and eight months when she was nominated for 1975's The Story Of Adele H), and Keisha Castle-Hughes (12 when she was nominated for 2002's Whale Rider). None of them won.
So what does a tomboy from Halifax, Nova Scotia, know about teenage pregnancy?
Not much apparently, but that is not the reason that director Jason (son of Ghostbusters director Ivan) Reitman cast her.
In the film's production notes, the 30-year-old Reitman says: 'A lot of actors are good mimics, or they are method actors and do a lot of research, or they are naturally very charming. What's different about Ellen is that she knows what Juno would do, say or feel at any given moment, and she can turn it on and off like a light switch.'
On her part, Page did little research other than taking notes from her father Dennis, a graphic designer, and mother Martha, a teacher, and co-star Garner, who has a two-year-old daughter, Violet, with husband Ben Affleck. 'I didn't want to be too analytical or else I'll get too judgmental about Juno,' she explains.
While she has been showered with awards and accolades, she does not want to take full credit for her performance. She would not have gone this far without the incredible script by first-time screenwriter Diablo Cody, which she thought was 'pure, natural, understated and casual'.
Cody, 29, whose real name is Brook Busey-Hunt, was an ex-stripper and her Juno script has already won the Writers Guild Association award for Best Original Screenplay last week.
Page, however, does feel responsible for the film's soundtrack. When Reitman asked her what music she thought Juno would listen to, she recommended the obscure New York band The Moldy Peaches. This led to a meeting between Reitman and the group's singer Kimya Dawson and the latter contributing a few songs to the soundtrack, including Anyone Else But You, the film's love theme of sorts.
Despite the hot-button issues of teenage pregnancy, abortion and adoption, Page maintains that Juno is still 'one of the brightest films I've ever done'.
She adds: 'It definitely has an optimistic and humorous quality and my parents are actually happy about it. It was nice for them to see me not torturing someone for a change.'
She is of course referring to her breakthrough role in the tough-to- watch-but-too-compelling-to-resist psychological thriller Hard Candy (2005), in which she played a vengeance-seeking teenager who used herself as bait to trap a paedophile.
For Page, Juno is not a political picture but a personal one about a girl who is forced to grow up too fast, too soon, and she knows exactly what it feels like, since she started acting in television at the age of 10.
'You are thrust into an environment with adults,' she says with a slight ambivalence.
'Though I get to live my life as a kid, in some ways, I feel older.'
With Hollywood knocking on her door, she is open to both studio and independent projects just as long as it fulfils one condition: The script is good.
Her only big-budget movie to date is X-Men: The Last Stand (2006), in which she plays Kitty Pryde, the good mutant with the ability to walk through solid objects.
She is expected to start work on Drew Barrymore's directorial debut, Whip It, which tells the story of an indie-rock loving misfit who fights small-town ennui by joining a roller-derby team. No prizes for guessing who Page will be playing.
'I just want to play whole, honest individuals whom I can really sink my teeth into. Something that's gonna challenge me,' she stresses. 'When you read something that gets you excited, it's something you want to give yourself to.'
