In many cases, you can put the boat on your homeowner's insurance, or in your case, your folks might be able to put it on their homeowner's policy. The thing is, it's usually cheaper (a lot cheaper) to add the boat to an existing homeowner's policy than it is to get a separate, specific policy just for the boat.
There are some restrictions to adding a boat to a homeowner's policy, but they usually have to do with larger, more powerful boats, or leaving the boat in the water year round, or taking it out on the ocean. With a small boat that you only use on the lake during the normal boating season, you should be fine.
Also, in addition to your safe boater education class, you might want to take some on the water instruction. If you do, try
www.jpboating.com for private instruction on the lake, using your own boat.
Good luck, and feel free to ask if you have questions.
Rob