"Oh, Lordy! Here's another wild and wooly one!"*
Since you're so committed, I'll skip usual advice of starting with a 15-16' daysailer. Get an 18-20' 'pocket cruiser' (with a keel, even if it's a shoal draft) and get familiar with sailing it in the bay/harbor. Then go on the ocean. Go up the coast a few miles and make it back. Go down the coast a few miles and make it back. Go around those islands that are just a few miles offshore and make it back. Pack some food and water and go away for a few days and make it back. Then do it all again.
If you spent a season or a season and a half doing all of that, you would have answered a lot of your own questions; you could also chime in on here and help answer other people's questions.
It's fun and gives me a warm fuzzy feeling.
Now that you're a little bit salty (you'll know because barflies will lick you before they take a shot of Tequila) you can move up to a 27-30 boat which might be 'the boat'. Get comfortable with that boat and improve on all of your accomplishments from the smaller boat. That should easily take 2 more seasons.
Put all of that on hold and cross an ocean as crew on someone else's sailboat. Maybe you could do this a few times in the off-season. Get used to being crew as well as captain.
So, with modest money and a lot of drive, 4-5 years from now you could be at the helm of a small blue water boat taking on longer and longer passages and aquiring better and better equipment until you finally feel that you and the boat are ready.
Kinda makes me want to be young again.
*Can you name the movie?