Florida sets the age of majority at 18. Until 18, a child can not make legal decisions including choice of residency. A child can become legally emanicpated (become able to make legal decision) by a court prior to turning 18 but must show how they are making their own way. Probably not worth it based on the time frame in which she will turn 18 in a couple of months. The practical point is to discuss with the legal guardian, even if emotionally difficult to see if permission and coordination can be obtained. The other concern is what happens if minor is hurt in another state? Who has authority to consent to medical treatment? This is why you should consult with legal guardian.