Possibly, but what is more likely is telling her that you like her too much. If you want to have sex with her, and she does not feel the same way about you, it could end your friendship. Think about how she treats you, how she acts around you. Does she like to sit right next to you, and put her arms around you? Does she kiss you? Does she gaze into your eyes for long periods of time? If she is not doing any of these things, then she probably only thinks of you as a friend, which is still a wonderful thing.
It is easy to mistake friendship for desire, and to project your feelings onto another person, in that you desire the person, so you believe that she desires you. Do you put your arms around her, and hold her close? If so, how does she react? Does she pull away, or snuggle up closer? Non-verbal communication is often the best way to gauge how a girl feels about you, because sometimes people have problems expressing their feelings in words.
Don't be in a rush! Friendship is a very important thing, and can last much longer than a sexual relationship.
I had the same problem. I became good friends with a girl. For 4 years, we've been friends. Until one day, I discovered how much I truly need her in my life since she went on an "Extended Holiday". For 3 weeks, I sat by myself, not inviting anyone to comfort me, thinking I can live with it. The Monday she came back, before school, I was for the first time in my life, excited to go to school. In the time she was away, I confessed my feelings to one of my best guy friends, who I've known for 8 years (Out of 14). I know that might sound gay but, I told him and he said he'll ask around if she feels anything towards me, other than friendship. Well, one day I told her a month or 2 later, and she said exactly this "I'm not ready for a relationship, I just can't deal with the stress". So now, I haven't said more than 100 words to her in the last 6 months.
So this is my advice to you. DO NOT, unless it's inevitable, tell her that you have feelings for her. Just stay her friend, and be as kind and as nice as you possibly can be, without over-reacting and being a freaky guy. Just do what YOU think would be the best way to approach her.
Good Luck :) Best Wishes.