Advice on girl's point of view in this situation

I'm 19 and a senior in high school. I saw this senior girl at a track meet a while ago and I can't stop thinking about her. She was honestly one of the most beautiful girls I've ever seen and all I want to do is talk to her at least once. She goes to a school a few towns over and I keep seeing her at track meets.
i was going to go over and talk to her, but after talking to some other people, I found out that she has a boyfriend and they have been dating for over three years now. The kids on her team told me a lot about her and we are so similar. I want to talk to her and get to know her more, but I am a little afraid to do that because she already has a boyfriend and I don't want to be an idiot that just goes up to her and embarrasses myself in front of her and all my peers who I run with. I could use some advice with this and any help is much appreciated. Thanks!