Substitute yogurt, cheese or calcium fortified juices and cereals if milk is not preferred. Teen girls tend to be deficient in folate. It is a B vitamin needed for cell division. Folate is high in dark green leafy vegetables, seeds, beans, and orange juice. From a tactical standpoint, it is best not to pay much attention to the pickiness.
Many preteens are very finicky eaters.
Encourage eating a variety of foods, but don't make an issue out of it. Allow her to skip breakfast in favor of a mid-morning snack. It is often hard for some kids to eat in the morning, despite the importance of doing so. See if you can pack a healthy mid-morning snack into her backpack for school, such as a homemade muffin or granola bar. Thank you for your important question.