ymiri,
Get on the dinghy! The best sailors are almost always people who came up on
dinghy - because a
dinghy is unforgiving, you learn the sea state, wind and sail trim in a way that would take much, much longer on a keel boat. In fact with respect to sail trim you can look about on any given weekend and see dozens of happy keel boaters, utterly clueless (or careless) about sail trim.
Lots of respect for Jane's accomplishment, but she is
wrong on this one.
Once you learn to sail - the difference between a
dinghy and keelboat is many things, but mostly learning its inertia and momentum.
Seamanship on the other hand is a rather slowly acquired accomplishment through experience and mentors.