As one who has spent most of his life doing things ass backwards, I welcome you. Like you I bought Windmistress having never been on anything larger than a windsurfer, and even there I used the current far more effectively than the wind. My first experience was to single hand the boat home from LA to San Diego. What I learned is that there is a lot to learn, that sailing under good conditions is very manageable, but that it won't be long before you must sail in poor conditions and that will quickly separate a sailor from a fool.
How you learn should govern what steps you take to go from fool to sailor. I do pretty well learning terminology from books, so I started there. I did take the 101 class, which is a group session, and although I can't fault the class, I did not get much from it. Got much more from reading Don's book and then laboriously taking the chart out and trying out the concepts on the water.
Then you need to learn how to read a chart and how to use whatever electronic aid you plan to rely on.
If one plans to make any kind of a voyage, my humble opinion is that someone on the boat needs to have some mechanical aptitude. Things go wrong with boats, especially old boats. You need to have some idea where to begin to diagnose, fix, or at least disable, whatever threatens to disable the boat. Rewiring Windmistress has been a labor, mostly of love. But at least I feel that in addition to having improved her, I have some idea how she is wired and plumbed. May not make her feel any better, but it certainly makes me a little more comfortable.
One thing often overlooked. Make notes and drawings as you go. Compile information on your boat and organize it into notebooks. If you sail inland or very close to shore, you can probably keep it at home. If you venture farther, keep it on the boat.
Finally, I cannot overemphasize the value of this forum. From lessons on trim and mechanics to outright help, the folks posting here have, for me at least, been the soul and sole of my boat.