Under normal circumstances, you'd expect a 16-year-old girl to be intimidated by the hoopla that surrounds the promotion of a major motion picture. And Gavin Hood's adaptation of Orson Scott Card's Ender's Game – a gung-ho space opera concerning teenage space cadets – is no sort of boutique production. Co-starring Harrison Ford and Ben Kingsley, the picture has all the bash and flash you expect from an autumn tentpole. Ford, chief grown-up, is on his way to Graham Norton. Meanwhile, the juvenile cast have gathered for conversations in a glamorous West-End location.

You couldn't honestly say Hailee Steinfeld looks fazed. Oscar-nominated for her performance in the Coen brothers' True Grit, Steinfeld has, like so many young American actors, a slightly eerie maturity. Maybe, we are the ones that should feel intimidated.

"My first round of all this was for True Grit," she says. "I didn't have any idea what I was getting into in terms of the press and junkets and interviews. It's definitely weird. I do find it interesting. I love the travel. And I'm talking about stuff I like to talk about. So, I don't complain."

Then there’s all that red-carpet stuff. She has to swan past legions of idiots flinging lunatic questions in her general direction. Nobody can be prepared for that.

“Red carpets are part of the job,” she says. “But they do also make for some of my best film memories: the getting dressed up: the cheers, the beautiful clothes.”

Steinfeld already radiates quiet professionalism. Raised in a comfortable section of the San Fernando Valley (the same neighbourhood that gave us Paul Thomas Anderson), she certainly trades in relaxed California vowels. But you wouldn’t identify her as any sort of vacant Valley Girl. Rather than peppering her conversation with “you knows”, she punctuates each answer with careful qualifiers such as “somewhat”.

Her dad is a fitness instructor. Her mother is an interior design. There are no obvious family connections to the entertainment business. So how did she find herself where she is today?

“Well, I never really found something that I loved as much as I love acting,” she says. “Before I asked my mom if I could start acting I asked her if I could start basketball. That was just a week before. So it just came about as the thing that I wanted to try at that particular moment. That was what interested me that week.”

Clean of diction and with a striking, round face, Steinfeld began appearing in the odd short film when she was just eight. Then, in 2010, she landed the sort of role that makes careers. There have been few more absurd examples of category fraud than the one that found Hailee receiving a best supporting Oscar nomination for True Grit. She is in virtually every scene of that western and she is magnificent throughout. Solid, articulate, righteous, the 13-year-old came across as the adult to Jeff Bridges's petulant child. It is estimated that as many as 15,000 girls tries out for the role. Did she understand the significance of the audition?

“I was somewhat aware before I shot the film,” she says. “I have much more awareness of who the Coens are now. I remember reading for them. And it’s one of the coolest experiences I’ve ever had. Those guys are so amazing. They are geniuses. To have been a part of their film family for three months was an honour.”

It must be daunting to be the only young person about the place.

"I was the only kid on set in True Grit," she laughs. "That's if you don't count Jeff Bridges and Josh Brolin and Matt Damon. They are all big kids."

Not surprisingly, the young Oscar nominee was soon in much demand. She travelled to Italy to play the female lead in the recently released version of Romeo and Juliet. She has a significant role opposite Keira Knightley in Can a Song Save Your Life?, the latest film from our own John Carney, director of Once. And she has recently finished shooting Tommy Lee Jones's western The Homesman, opposite Meryl Streep and Hilary Swank.

It would be crazy to suggest that anybody should feel sorry for her. There are worse ways of spending your teenage years than sharing onset catering with Meryl Streep. But successful young actors do always end up sacrificing some of the everyday pleasures of youth. It is, perhaps, for this reason that actors such as Claire Danes and Julia Stiles followed Jodie Foster's example and took a university degree. That way, they get to enjoy a modicum of normality as young adults.

“The job does get in the way of normal teen things,” Steinfeld says. “The prom and homecoming are things that happen when I’m out of town. And I am home-schooled. But I like to think that I’ve had experiences that stand in for those things. And I have a really great group of friends that are just a phone call away. I’ve never missed out on anything big enough to get in the way of enjoying what I was then doing.”

When you read how rigorously she has analysed the dynamic of her life, you can easily forget that she is still just 16. At that age, many of us were still getting are heads stuck in the banisters. Then again, she is constantly surrounded by industry veterans. Ford, Kingsley and Viola Davis were all at her elbow in Ender's Game. Advice from wise old heads has, one imagines, not been in short supply.

"I felt that starting out with True Grit," she says. "I've been surrounded by people who have been doing this forever. And from that I see people who come to work, who do that work and who, at the end of the day, go home to be with their family. And that's how I look at it."

How terrifyingly sensible she seems. She will surely cope with the new challenges that Ender's Game brings. It's not just that the film is a big, green-screen epic – though it certainly is that – there's also the fact that the Ender books have an enormous following (notwithstanding Mr Scott Card's notoriously negative views on marriage equality). Steinfeld plays one of several young people recruited to help defend the Earth from attack by giant insects in hurtling spacecraft. Just wait for the online chatter to begin.

"Since I shot my first film, I appreciate cinema as an art more," she says. "When you understand the number of people involved and the amount of effort that goes in from all departments across a shoot, you see film differently. You appreciate the work more. Yes, Ender's Game was on a much bigger scale. I've never been involved with anything like this. It's a film that comes with a ready-made fan base, but you also want to introduce the material to people who don't know the books."

Has she got over the excitement of meeting magastars? Surely, all that must seem commonplace now.

"Oh I get starstruck all the time," she says. "I get tremendously nervous. I did that film with Tommy Lee Jones and Meryl Streep and I remember thinking: 'I can't do this. This is crazy'. I never thought I'd encounter people like them."

Such are the vagaries of the film business that we have seen little of what Steinfeld has shot since True Grit. Romeo and Juliet opened rather quietly earlier this month. Can a Song Save Your Life? received good reviews at the Toronto Film Festival, but will not be released here until well into 2014. There is every possibility that The Homesman might get delayed until next year's Oscar season. But it's clear that Steinfeld has managed to attack an impressive variety of work.

"This was only my third film," she explains. "And with True Grit and Romeo and Juliet, which are two period pieces, you're taught to take advantage of the props and period details you have around you. But I was really forced to use my imagination here. And it was quite an interesting way of working, because I'd never done anything like it before."

And she is suddenly flung into some proper action sequences in Ender's Game. The film is not short of dangerous-looking stunts.

“Oh this required far more physical preparation than anything I’ve ever done,” she agrees. “It helped that my dad does what he does and that I love being outside and being sporty. My parents and my brother are so supportive. They’ve sacrificed so much for me to be where I am. They’ve never really given me a hard time about anything actually.”

Well, that's nice. The occasional twerk-storm noted, we probably shouldn't worry quite so much about child stars these days. Our screens are now alive with folk such as Leonardo DiCaprio, Anne Hathaway, Claire Danes and Ryan Gosling who successfully (and largely painlessly) made the jump from juvenile roles to grown-up stardom. Still, I can't help wondering if she gets to listen to pop music and generally behave like a young fool.

"I listen to everything," she says. "My brother plays classic rock. I like Bruno Mars. I've always loved Bruno."

Get that “always”. I suppose Mr Mars would seem to have been around forever if you were just 16. Nothing seems to shake Steinfeld’s façade of balance and normality. Just consider that comment she made earlier about actors leaving the set and returning to the bosom of a average family. How stable. How unfussy. How grown-up.

“It’s doing something you love,” she says. “But there’s nothing more to it than that. Your life is elsewhere.”