Suggest giving her milkshakes (ice cream, fresh fruit or frozen fruit, milk) or yogurt smoothies (yogurt, fresh fruit, and frozen fruit) instead of
formula and for additional calories,
protein, and vitamins and minerals. She can help make them, too. For her age infant formula will not provide the nutrients she needs. The most important thing is to RELAX. Let her eat what she wants. Slowly introduce new foods, and if she does not want it, do not make a fuss over it.