Its called shivering from the fall in temp.
Shaking is a body protective mechanism to produce heat within the muscles. It doesn't depend on the age actually but depends on the type of fever a patient is having. I feel your daughter is having most probably a viral fever, however better to consult your family doctor. thanks
Shaking is not that uncommon with a fever. You should try to get her in to see the Dr today to find out what's going on. It could be a virus, the flu or any number of things. Is she having any other symptoms besides a fever and shaking? Remar