She can be emancipated if she has a means to support herself, even a part time job. Emancipation requires her to be ready to be an adult, ie. supporting herself, getting a place to live, etc. If she has a rental contract with you, a job to buy food, etc., she has a good shot. A contested emancipation would not be worth the costs for less than one year nor would a guardianship.

Depending upon your relationship with the parents, you might be able to convince them to sign a temporary guardianship. In Nevada, we have a single page form that will give you a six month guardianship. If you want to do the forms through me, we can do it by U.S. Mail.