alk about a girl who has it all! Reese Witherspoon is sitting on top of the world these days, both personally and professionally. The 25-year-old dynamo impressed moviegoers this summer in the comedy Legally Blonde, in which she played - what else - a blonde student who takes on Harvard Law School.   "I think there are parts of me that I incorporate into all my characters," Witherspoon told me during a recent interview in Los Angeles. "Also, there are parts of people I know. It's hard to separate what is like me and what is like someone else - but I think I'm a very positive person. I always look at the bright side of things."   About her new movie Legally Blonde Witherspoon says, "I just loved the juxtaposition of this woman being so girly and also being very strong, tough and smart. Personally, I think that women are all of those things and it was a real joy to play her." According to her Legally Blonde co-stars, it was a joy to work with her. Selma Blair, who also co-starred with Witherspoon in the film Cruel Intentions, has remained close friends with her and couldn't be more proud of her pal.   "She just gets better. I've been lucky enough to have Reese in my personal life for a couple of years now and I've always admired her," says Blair. "She has gotten more capable and has become a very strong actress and a woman who knows what she wants."   Witherspoon made her feature film debut at the age of 14 in the film, Man in the Moon opposite Sam Waterston. While many young girls only have to worry about adjusting to their teens, Reese was well on her way to becoming a star. Other film projects soon followed with roles in the Diane Keaton directed TV feature Wildflower and Jack The Bear with Danny DeVito.   Then, in 1998, Witherspoon started to get some meatier roles in films such as Pleasantville and Cruel Intentions - and then there was her stand-out performance in Election in 1999. Making Cruel Intentions not only turned out to be a great move professionally, but she starred opposite heartthrob Ryan Phillippe and the two fell in love. "We were both young, but we just knew it was so right," explains Witherspoon.   The couple have since married and have a two-year-old daughter whom they are just crazy about. "Eva cracks us up," she beams. "Every day she does something new that just fills us with awe. Her new favorite pastime is running her hand over Ryan's new Mohawk haircut; she thinks it's a rug," Witherspoon says with a giggle.   "You know, being a mom is great but I'm the first to say it's tough. I am just so happy that I have been able to keep up my career and have a baby, and it helps so much that my husband is willing to do so much; he is so great with the baby."   When the couple aren't busy changing diapers they spend time looking for another project to star in together. "We really enjoyed doing Cruel Intentions and we are very excited about finding something else; it's just about finding the right script."   As for the possible future day when Eva comes to them and says she wants to be an actor, Witherspoon is keeping an open mind. "You know, I just try to be encouraging in whatever she wants to do," she says. "I just want to be supportive - that's the kind of mom I want to be."   Up next for Witherspoon is a starring role in The Importance of Being Ernest. She'll be holding court with the likes of Colin Firth, Frances O'Connor, Judi Dench and Rupert Everett. Not too shabby indeed! - Bonnie Laufer-Krebs