If you're in the United States, then there are no legal concepts of arranged marriage. They can put whatever they want down on paper, but there is no legal obligation on either of the two parties involved to do jack shit. If she doesn't consent, she doesn't consent, and cannot be legally forced. That said, there's nothing that says they can't disown her, although considering her age they likely can't legally be kicked out of the home (child abandonment/endangerment. Look into the legal aspect, as previously suggested, as in some jurisdictions attempted arraigned marriage can actually be legally construed as a form of 'endangering the welfare of a minor'. This isn't just true in the US, it holds for a lot (if not most) of western countries.