Hi PKK20, If you havent used any grace period (either before or after the start/end date of OPT and there after). You have 60 days grace period (to maintain your status). Since you only seem to have a period of 20 days you are good to go. You dont need to enroll for any class or anything. Again, like I have mentioned earlier , I am not a legal expert. I have known this all from my past experience and my own research. I am pretty sure about what I have mentioned above. But to be on the safe side talk to a lawyer (normaly they charge you around $ 75 for consultation). Good luck again.