I think you can do it. I am certain there have been times when you were building a house where you finished a task you never did before. You put your experience to work and accomplished a fine job. Your brain is an incredible tool, so use it while building your boat.
I never casted three tons of lead for the life of me until last week. I was ready to start over if I failed. I never took delivery of a 26 foot beam of Douglas fir, but there it sits ready for simple tools.
I you've spent more than thirty minutes untangling a mess of string and found it a bit intriguing, then you have the mental stance to learn as you go.
Look for an old greenhouse frame and offer a fair price. But you can build outside too, at the whim of the weather while treating your wood to pine tar, linseed oil and turp.
If you don't have the plans for your boat, order them today. If you do, then start lofting.