There is no set age for Invisalign Teen. It depends on what teeth are in the mouth. As long as all the adult teeth have erupted into the mouth, Invisalign Teen can be used. Invisalign itself says that the first bicuspids must be erupted in the mouth, but not the second bicuspids and Invisalign Teen can be used. Typically this is sometime between 10 to 12 years old. If your daughter has the necessary teeth erupted into her mouth, she should be able to be treated with Invisalign Teen. Your best bet is to see an orthodontist for a consultation to discuss treatment.