If there is nothing wrong with her, for example physically or mentally (not just being sad to be away from family and friends), than her only option is to honor her enlistment contract, it is the adult thing to do. If she does not return, she will be AWOL, and after 30 days, she will become a deserter, and a federal felony no bond warrant will be entered in her name. That means if she is stopped for speeding or rolling a stop sign, she will be arrested and returned to military control. Its better if she just honors her committment.