To come to the United States to study, you will need a valid visa issued for the school which you plan to attend. Most students come to Saint Joseph’s on an F-1 Student visa, but a few come on J-1 Exchange Visitor visas. To apply for your visa you will need to pay the SEVIS/I-901 Fee and then visit a U.S. consulate, preferably in your home country. It is important to apply for your visa early to allow time for difficulty scheduling an appointment, delays in processing, and possible security clearances. However, the consulate cannot issue your visa any more than 120 days before you will start classes. Once you have your visa, you will want to prepare for your journey to the United States.
Please note that your visa tells you until what date you can enter the United States. The expiration date does not mean that you must exit the country by that date; it simply means you will not be able to use the visa for entry purposes after that point. You will be admitted to the United States for the duration of your studies so long as you continue to be enrolled as a full-time student and to follow all of the regulations that govern student status.
Since you are coming to the United States to study, you must come on a student visa. Do not enter the U.S. as a tourist with either a B-1/B-2 visa or a WT/visa waiver. You cannot study in the United States as a tourist so this will not help you to begin classes any sooner. It can also be very difficult to change from tourist to student status, and it is especially difficult if you have already applied to or been accepted by the University before you enter the country as a tourist.