‘Twilight’ star Kristen Stewart may just be 20 years old, but the actress says she feels like she’s been a grown-up for years. “I felt like an adult when I was five! And I really feel like nothing has changed now I’m officially an adult,” says the brunette celeb, who stars as heroine Bella Swan in the vampire movie franchise. Kristen also says she was glad to stop going to a formal school at the age of 14, when her parents switched her to home schooling, because she didn’t fit in. “I was really happy to leave [school] – it took a big load off my shoulders. School is like a little hierarchy and I was glad not to be part of it.” Now a global star, Kristen says she’s pleased with her lifestyle. “Working on movies has taken my time away, but it’s been filled with something so different and fruitful, I’m in a very happy position.”