You'll never convince anyone that way...
Take her to a concert, watch a good rock movie with her (there are a couple...), something that heps her get a more visceral experience.
Frankly, if someone doesn't like something, they usually won't give it a fair try. You could make me a tape of Reliant K and Skillet, for example, and I probably wouldn't listen to it and would dislike it if I did...
She doesn't have to like the same music as you; it's really okay.