I had a student deferment up until May 1970, when I failed the the pre-induction physical due to an ear infection.  I was retested in November and passed. 

I got my I-A classification in December 1970 after the December call had already been issued.  President Nixon extended the eligibility for those who had gotten a late reclassification in 1970, and thus I was drafted into the army in February 1971.