Picky girl

Anyone that knows me and my daughter Lily, knows what a picky eater she is. Her list of things she will eat is very small; I try to introduce her to new things but that usually results in her gagging and throwing up (not fun when out in public). If it doesnt involve cheese, chances are she won't eat it or go near it. It's frustrating because not everything is covered and smothered in cheese and I want to be sure she is eating healthy and getting more nutrients but she is so stubborn and difficult that it's almost impossible. Even hiding veggies in her food doesn't work, she knows her cheese and she knows when it doesnt taste right!