My two cents
Here's my perspective:
I took the US Sailing Basic Keelboat course last fall and jumped into the Basic Cruising course to follow up on it this past weekend. I don't own a boat and don't have much experience. In the BC class with me were two guys who already owned boats and were looking to learn more about how to sail them.
One of the guys who owned his own boat and had been sailing it for years dropped out after the first day of class. He said that he didn't understand a thing the instructor was talking about (vocabulary...). He said that he had no idea why were doing what were doing (sailing theory...). He said he must have been put in the wrong course, and I can only hope that he didn't give up altogether, but instead dropped into the BK course.
The point is that self taught sailors can get to a certain point by themselves, but until you're working with others with an instructor forcing you to use the correct terms, constantly quizzing, etc. there's going to be a gap in knowledge.
Second point: If I were you, I'd take the classes now in smaller boats. Don't wait until you get your own boat. It may be worth it once you get your boat to hire an instructor for a day or two to go over the systems and establish procedures for the boat, but start laying down the background now.