Many top universities offer free college courses online. The courses are from Harvard, MIT, Wellesley, and other top institutions, and range from poetry to computer programming, from anatomy to archaeology and more. The free courses may be taken at your leisure (if you’re not pursuing a certificate or credit, both of which are available), but assignments are due within selected dates.
Our eldest is attending a four-year university, and I can see how it would have benefited him to take one of these free university courses before attending college. Even if no credit was received, it would have given him experience with a university professor and with assignments and due dates (especially due dates!).
Browse the listings of free college courses at edX. To view which courses are starting soon, click on “Starting Soon” on the right sidebar.