I am all about this method. you offer food, she choose what to eat. don't make it a power struggle. she is eating ok for a four year old. try making new things with her but don't pressure her to taste food. if you are worried see a feeding therapist or a pediatric gi. does she enjoy cooking or baking or grocery shopping with you? those are fun, non pressured ways for her to have exposure to new foods. I can give ideas of what to make with her
