An F-1 student is NOT required to be enrolled during the Summer semester UNLESS the summer semester is the student’s first semester in which case he or she must enroll in at least 6 units.
First semester 면 들어야 한다고 나오네요.
최소 6ᅟunits만 들으면 된다고 하는데 정확한건 학교에 문의해보세요.