Currently On H4 planning to change the status to F1 so is it must to be one full year on F1 to get OPT?


I am currently on H4 visa and will be joining a college for Fall 2017, and am planning to change from H4 to F1 once I join the university. I am struck with one question since the change of status takes minimum 6 months, is it must to be on F1 visa for one full year to be eligible for OPT? or the duration of course which I have completed on H4 will be considered as well?