We went from a 26' power boat to a 42' sailboat. Took no lessons. Just jumped in and did it.
So far all we have done is cruised the Great Lakes, down the inland rivers to the gulf, down the west coast of Florida, around the keys, up the east coast to Cape Cod, back south to Florida, across the the Bahamas for the winter and now headed back up the east coast. Some ICW, some coastal overnight hops, East River of NYC, Gulf Stream, anchorages, moorings, marinas, 60+ locks, inlets, tides, currents, 40 knot winds, 12' seas.
No disasters, a few soft groundings, lots of fun.
So no, you can't do it. It is dangerous, extremely difficult and only for those with several decades of sailing experience. Stay home!