The bottom line is that only you can make the decsion - just make sure it is an informed one. What I would say is, that unless you can say with absolute certainty you will be on a command course in the next 6 months then you should assume nothing. For what it is worth, I personally know several of the 80+ FOs who are in the 'command pool' awaiting courses and not a single one of them have been given a definite date. If you do not have a date then, in my view, you would be extremely unwise to assume only 6 months' wait.
Best of luck anyway - whatever you decide.