I think you should sign up for the Coast Guard Auxillary or Power Squadrons Boating safety Course. I think you retain much more info in a classroom setting than you do with a basic online course. And you get the Certificate of completion with is becoming more and more mandatory in most states as a somewhat defacto boaters license. It's well worth it. The courses are free. You just pay for materials.
Here are some links for you;
http://www.boatma.com/learntoboatsafely.html