I am definitely on the "just do it" crowd. I grew up on the water but my only sailing experience was racing a small tri-hull with friends and teaching puffer handling at summer camp.
Now some 35 years later I get hooked so I go out and grab a 30 year old US27 and can't wait to get to know it next summer. Don't get me wrong, if you have zero experience on the water you do need a safety course under your belt but you don't need a $20K boat and another $3K in school to get it to move.
Just do it....life is out there