The actress said that she has come to appreciate how much Bella has grown over the course of the films.
Stewart told Vogue: "[She's] a character who is embedded in so many people's psyches at this point. It's starting to enter my head a lot more than it used to because it's at the end and it's come such a long way."
She also admitted that she wants fans of Stephenie Meyer's 'Twilight' novels to be happy with the film adaptation, rather than casual viewers.
"I just want the fans of the book to be happy. I don't necessarily care about anyone else," she explained.
The latest instalment of the films, 'The Twilight Saga: Breaking Dawn: Part 1' will be released in cinemas in November.