Can I start a course at any date/time?

Most colleges require you to start a session on a specific date which coincides with the start date of the brick and mortar students. Many times the professor will record on campus lectures for you to view on your own time which is asynchronous and many with host live sessions in which you are to participate in the class discussion as a whole and that is called synchronous. If you are truly looking to take courses on your own time, it is imperative that you make sure the college offers asynchronous classes.