Yes. Critical is the way of her entry. If she enter the country illegal, sorry, no possibility. Regardless, is she marries a US citizen or not. However, lets say she enters the country as a student, or as a visitor. If her parents are US citizens, they can apply for her. Siblings too but the waiting period is horrible. Almost 25 years. OR, if she married a US citizen she can. She does not have to leave country. Huge mistake if she did. Some attorneys will suggest it, to make case longer and charge more money.