I don't know how long she'll stick with it (and I'm hoping for a while - I don't have many friends with an interest in music), but if it's older than 1990, she's really not interested. Which won't help her much, IMO.
Ouch, if she's not interested in anything older than 1990, she's missing out on a lot of great stuff.
Really trip her out, play her Miles Davis' "Kind of Blue". Or Dave Brubeck's "Take Five". Or Weather Report's "Birdland"...