I don't think I'd sign up for a Craigslist sailing instructor, but free lessons from a willing friend are ok. If you're paying
, a reputable school is the best route.
I grew up in Cape Coral.
If you pay for a sailing school, you'll learn how to sail on a small boat. This will make you a better, big boat sailor. Hopefully it'll also help you decide if you want a small boat, or if you really want to step up to that 30 footer.
I initially taught myself on a 25 footer. I read a lot, and used the web. Then I made sailing friends who took me racing. That was where I really learned a lot. This helped me refine my boat parameters and I've settled onto my "long-term" boat.