The South Africa-born star explained that it was an incredible challenge to take on a character who has so few inhibitions.
"I'd be blind to not see the potential in the character. These are the kinds of roles women wait for," Theron told USA Today.
"It scared me. There's so much about her - when you hold up the mirror, you see almost too much you don't want to acknowledge. But that coincides with what makes my job exciting."
Theron went on to say that she was determined to avoid movie clichés while working on Young Adult.
"I didn't try to make her a human being. I really believed that she was. There's so much about this that's hard for me to admit, that I've done things like this to get through the day," she commented. "She does things that are really despicable.
"Overall, the survival techniques - the meanness, the lying about her life being so great - are things we can relate to."
The film's director Jason Reitman recently revealed that he would not have made Young Adult without Theron.
Young Adult is now playing on wide release in the US and opens on February 10, 2012 in the UK.
> Young Adult Patton Oswalt: 'Charlize Theron love scene a nightmare'
> Charlize Theron is the female Jon Hamm, says Patton Oswalt
Watch a trailer for Young Adult below: