Because of the traditionally high volume of US visa applications during the summer months, the US consulate encourages students to arrange an interview appointment in a timely fashion.
Under US law, student visas may only be issued up to 90 days before the start date listed on your I-20. However, please note that you are welcome to apply more than 90 days in advance. If you do so, the consular officer will determine during the interview if you qualify for a student visa; if so, you will just need to return to the consulate to receive your visa within the 90-day