Saoirse Ronan may be young, but she's had no shortage of juicy roles to challenge her in her almost 17 years. While she's been challenged before as an actor, her role in Joe Wright's Hanna as a sort of ass-kicking, modern-day fairy-tale princess was undoubtedly the most demanding overall, both for the complexity of playing a teenage girl experiencing civilization -- and all of the assorted wonder and baggage that goes with it -- for the first time, and for the physical demands of taking on a character trained since birth as a hunter and a killer.

"It was very intense," she told Spinoff Online at WonderCon. "I trained for about two months before we started shooting. I worked out in the gym and did different styles of martial arts. It took a lot of focus and it was probably the most preparation I've done for a film. It took a lot of concentration as well. I like that."

Playing Hanna presented Ronan with a unique opportunity, as we see this young girl take her first tentative steps into the real world as the film's second act unfolds. She's never known love outside of its dictionary definition, never experienced television, phone calls, ceiling fans ... really, anything and everything we take for granted in the 21st-century world.

"With Hanna, something that really helped me to become this character was wiping my mind clean of any experience that I had gone through, especially over the last few years as a growing girl," Ronan said. "She's never gotten to go through any of those experiences. And I got to see everything in a new light, so fresh and pure. It's something I've held onto actually."

Hanna is a hard movie to classify. There is action, but it's definitely not an action movie. There are these sci-fi fairy tale elements as well, but that's not a genre you can pin to it either. Even after seeing the film, it's difficult to describe as anything more than a story. Ronan herself feels challenged in trying to classify the movie as well.

"People have asked me how to describe this film, what you can expect, what you're going to get out of it, and my honest answer is I don't know," she said. "I think everyone is going to take different things away from this film because it tackles feminism and the objectification of women, especially in the public eye."

"Hanna herself is a misfit and a bit weird and she's not cool, and that's what I really like about her. The fairy tale aspect is certainly very strong for me. And as an actor as well, it was so surreal, the situation, the story, the characters, it was all quite magical. It kind of frees you up to do whatever you want."

Part of what was so freeing for Ronan was her director. She admits to not remembering much of her work with Wright on Atonement, but she felt his faith in her as a performer with every move she made and every path she took during production.

"I really felt like he had this belief in me that I could do whatever he asked of me. It's a very wonderful feeling to have as an actor, that the person that you're doing it for has this trust in you," she said.

"I guess when you feel that relaxed and that safe to try different things, you'll go on to the next movie and think, 'Well I did it on this and it worked out well, so let's try it on this one.' I guess it encouraged me to take more risks. He worked with me at two very impressionable ages, 12 years old and 16 years old."

Ronan also gives a lot of credit to the ensemble of performers she worked with, including Cate Blanchett and Eric Bana. While the story is very much hers -- it is right there in the title, after all -- it only comes together under the influence of this strong cast of well-developed, thinking and feeling characters. There are no few archetypes here, paper-thin caricatures. Everyone in the main cast brings a level of complexity to their roles.

"You could take any one of them and make a movie just about them," Ronan said. "It's a very rich story because of these people. We had such an amazing cast on this film. The make the story more artistic because of their acting, because of the level that they're at."

There is another vital character in the movie, one that never actually speaks a line but is nonetheless with you throughout. The music. Hanna features a soundtrack composed by electronic music-smiths The Chemical Brothers. The cast and crew had some of their work for the movie to listen to on set, but Ronan admits that they also spent plenty of time listening to the duo's 2005 album, Push the Button.

"I loved what they did with this film," she said of the soundtrack. "It's actually probably my favorite part of the film, the music. It's so important to the story and it kind of makes it complete. I found it really interesting that they bring a circus/fairground type of sound into these really hard beats, because the sound is innocence with an edge, which is kind of like Hanna. They're very clever, those two, very clever."

Looming over everything is this odd sort of contemporary fairy tale structure. "The structure of the story is basically ... about a girl who's lived in the castle her whole life and suddenly she breaks out and is introduced to evil and beauty and ugliness and all these different things," Ronan said.

"It's dark like a Grimm's fairy tale as well. All of the characters represent different characters in fairy tales that we've grown up with. For me, and for Joe as well, Hanna is like the Little Mermaid who is breaking to the surface and wants to be a real girl. The style of it as well is a bit like a fairy tale comic book."

"The thing that makes the story powerful for me is the strong characters that we have in this film, the story that surrounds them all, how they're all intertwined, how Hanna's journey is basically a coming-of-age journey," she continued. "It's about realizing that the world is not necessarily as beautiful as a Grimm's fairy tale, it's dark too. But it's not as simple or as basic as a fact out of an encyclopedia. It's somewhere in between. [Hanna] needs to find that. So it's basically about finding her way and figuring out how she fits into it all."

Hanna opens today nationwide.