If you have no local club you can join or go get lessons from, and are left with no choice but to learn solo.

You can learn solo if you live out in the middle of no where on your own land or someone's land you have permission to be on or from a rural paved road even; as long as it's out in BFE and no houses around for miles. Just be ready to hit the sim hard and have a big pocket book for plenty of covering, epoxy, spare balsa and wood to make repairs.

Getting in the air is not hard, it's the landing and flight orientation when the plane is flying at you that will bite you. Practice on your sim doing long even circles and figure 8's to get your hand eye cordination used to the flight orientation as iplane comes towards you. Next practice touch and go landings on your sim, then transition to landings. Once you have mastered the circles, figure 8's and landings; your not ready yet. You then need to bump up you sim winds speed to 10-15 mph and put your sims controller trims to the extremes. Once you've mastered that now go and put the trims to the extremes in the opposite directions. If you mastered the circles, figures 8's and landing with your sims trims at the extremes with the winds at 10-15 mph, you just might be ready to try a solo flight. Just remeber use your sim as a learning tool, not as a game were you banging the sticks; use it to learn the subtle stick movements it takes to fly a plane.

So to answer your question, is it dumb to learn without a trainer/intructor; yes it can be considered dumb if you try for the instant gratification on your own; but if you take the time and seriously learn what it takes to solo flight on your own it can be down, lot's of flyers are self taught, while others learned from a instructor or like me were it was a combo of self taught with a couple of buddy box flights. Only you honestly know your skills and learning curve, only you can honestly tell yourself yes I can learn to fly solo properly and take my time doing it or no I don't have the patience to learn to fly solo properly therefore it's not a good idea. To each his own.