I think you can do it. I did same but it was way back in 2001. Just talk to your school and have your paper-work ready (letter from school etc) and tell them you have some family emergency. I left 2 days before school started (Jan 16, 2001) and stayed in Nepal for 3 months….. (Wow, I wish I could do that now). I also registered summer classes before I left so I could furnish paperwork to immigration incase they want to see it. Good luck and enjoy your visit.