Approved F1 Visa but two time deferring the admission


My F1 Visa(5years) was approved on December 17,2012 but due to 221g, I got VISA just week before of reporting date of univ(Spring 2013, jan 3), So I deferred my admission to summer 2013 giving 221g reason as I was not fully ready at that time.

But due to some family urgency now I am not able to go USA for summer, I also cancelled my ticket which I booked in January.

Now I want to attend Univ for Fall (August) on same F1 VISA.

I want to know whether my VISA is valid for FALL? and would I face any problems at immigration?.

I also informed my univ about this and they told me on phone that they accepted my request and processing my request to send new I-20 with same SEVIS as it will take one week time to process to send confirmation mail .