Starting out big
Maybe it''s just personal preference for the way I learned, but I''m definitely with Jeff on this. I think you are much better off putting in some time on the tiller of a sailing dinghy, preferably racing, before graduating to a boat that''s bigger than your car.
One advantage is that you learn intuitively that a boat is a dynamic system that has three degrees of freedom; like an airplane, it can roll, pitch, or yaw about three axes. And its motion about these axes is controlled both by natural forces (wind, gravity, buoyancy) and by how you choose to harness and distribute these forces using sails, weight distribution, centerboard, tiller, rig tuning, etc. The first time you sail a dinghy downwind in a blow, for example, you learn (one way or another) about the need to: Depower the sail plan (turn downwind, shorten or drop sail, etc.) and/or move your weight aft. If not, you learn how to pitchpole. When sailing a catamaran with a trampoline, you have fun heeling the boat enough to bring one hull up out of the water, and when the puff hits, if you aren''t expecting it, you learn about windage (things besides sails generate force due to the wind) and the "point of no return", where the Center of gravity gets outside of the center of buoyancy. You learn how much easier it is on the boat and on yourself to "park" the boat on a windy day by heaving to, rather than just luffing sails. When racing, you learn how to tell not just when a sail is luffing, but when it is stalled from being oversheeted by seeing other boats pull away from you. Adjusting the sheet gives you almost instant feedback to help you find the "groove". You learn about pointing and leeway by comparing your performance to other boats.
You learn all these things quickly, because the boat tells you through your hands, ears, eyes, and the seat of your pants whether the things you are doing with the sails, centerboard, tiller, crew weight distribution, etc. is having the desired effect.
You learn the behavior and capabilities of a sailboat intimately enough that, whatever situation arises, you can think of at least two or more techniques to deal with it (need to slow down to avoid a collision? Unsheet sails, backwind the jib, throw the tiller back and forth vigorously. Rudder broken and unrepairable? Steer the boat with the sails, or use a canoe paddle strapped to the side of the hull. Motor dies coming in to the slip? No problem; you know techniques from your dinghy sailing days on how maneuver to a dock under sail alone)
I''m sure you can learn all or most of these things by sailing a big boat, but as Jeff points out, the learning curve can be steep, especially if you don''t have a knowledgeable guide along with you to point out these things. For example, you take your big boat out in light winds. The wind is blowin, but the boat ain''t goin. Why not? Is it stuck in the mud? Are the sails stalled? Are you just stuck in a hole in the wind? Is a tidal current pushing you back? It could take you quite some time to differentiate between all of these different possibilities on your big boat. On a small boat, when you let out the sails to see if they are stalled, the boat''s angle of heel changes more noticeably. On a small boat, when you push the tiller over too hard and too quickly at low speeds, you notice right away that the boat doesn''t respond properly, and tends to slow down too much. On a big boat with a wheel for steering, you might have a hard time figuring out why sometimes the turns work well, and sometimes they don''t.
Sorry if this seems long-winded and is not what you are looking for (anecdotes from those who have learned on big boats), but as someone who learned on small boats and catamarans, and still sails both small and large boats, I hopefully have a perspective (like Jeff''s) which can be helpful for potential learners.