It’s easy to enroll in NIU ROTC. If you are a freshman, register for MILS 101 when you register for your courses in the fall or MILS 102 in the spring. Also, if you enroll as a freshman or sophomore, you don’t have to commit to service.
If you have prior service, or are currently in the Army Reserves or National Guard, you can receive credit for the basic course and forego the MILS 100 and 200 level courses with permission from the department. You will have to be a junior to take 300 level MILS courses, however.