Does she know what it is about the foods that she dislikes? With me, it's less taste, and more texture that is the problem.
I'm afraid I was one of those fussy kids, and I am repeatedly told that I'm still fussy, but because I cook for us, I don't really notice! I love food and cooking and learned from my Mum, who was a trained, qualified chef.
But....I still mave a massive list of "untouchable" foods that will never, ever, touch my plate, never mind my lips. My ten year old diet was rubbish - no meat, no dairy, no nuts, no fish. I'd eat chicken, breads, rice and pasta, every fruit, all veg except mushrooms and, of course, sweets (but not chocolate, it still gives me the dry heaves). I learned to cook so I could cook the foods I liked, and by doing that, I added beef, some pork, most cheese and milk to my diet without really being aware of it.
I'm rambling but what I think I'm trying to say is that she WILL get there, in her own time, and that even if she stays fussy, she'll cope with it, as I do, and have a healthy, balanced diet that works for her.