My kids were familiar with secular music, and liked some of it when they were in their teens. Now, as they’ve advanced in life to being yeshiva bochurim and post-seminary, they’ve opted out of their own accord. We always discussed why certain secular music is inappropriate. Perhaps I’m of the school of thought that with kids, if you make something totally ussur, you’re actually making it seem more interesting to curious kids.
Enroute to one of my kids in Israel is a CD of Beatles music (instrumental) as performed by Arthur Fiedler and the Boston Pops Orchestra. This was a suggestion one of her rebbeim in seminary gave her as a kosher way to enjoy the music she likes.