The actress attended the New York premiere of the new flick yesterday, nine months after it premiered in Utah during the Sundance Film Festival.
While at Sundance, Kristen told MTV News that she thought of the role as the most personal of her career to date, which changed her in a certain way.
And director Jake Scott is in agreement, as he has noticed a change in the 20-year-old since he worked with her in 2008 on the movie.
He said: "She's grown up, she's a woman now.
"It was an act of courage on her part, especially when you consider she was just 18."