How should I ask her to prom

We are seniors in high school. I like her, she likes me, but she does not want a relationship right now and even backed out of formal back in December because she did not want to "create mixed feelings." That was 3 months ago and a lot has changed for both her and I and I have talked to a couple of her friends and they have talked to her and she has said she would go with me but is nervous about me making a move on her (which I was not planning on doing) and that she is not sure whether I want to be more than friends or not. I very much do want to be more than friends but I respect the fact that she does not. Also, she has had some traumatic experiences with formal and prom in the past (ruined relationships, spiked drinks, and sexual assault). I know this b/c she has told me. She is comfortable with me and she knows I would never do anything to hurt her which makes me feel like it would be good for us to go together. We can go to prom, have a good time, and not have to worry about anything bad after.

So, how can I ask this girl to prom? I want it to be different and creative but at the same time, I do not want it to be too romantic and what not so that she does not get the idea that it is more than just friends.