I "learned" guitar in my teens and early twenties (completely self taught). However I never did manage to get by the d**m F chord and stopped playing for over 30 years, getting immersed in a career and other mundane interests. Never lost my love for folk music, tho' and decided upon retirement I was gonna learn to play guitar! The first thing I did was find a teacher, in order to learn things right before I had a chance to get bad habits ingrained.

My teacher worked with me from the standpoint of working out songs that I liked to play, with advice on proper playing techniques and a modicum of theory sneaked in, almost without my knowledge. Although I'm often frustrated at my progress (or seeming lack thereof), I'm glad I started with a teacher. Yes, he even sneaked in the F chord, bit by bit! I'm afraid without his help, I'd have continued on my course of 30+ years ago and become frustrated. Now my biggest frustration is finding enough time to play everyday.

So I guess I'm agreeing with both Racer and Peter T. Although it's fun doing the things you want, I think a teacher can do wonders setting you on the right track. And a basic bit of theory can certainly accelerate your ability to find comfortable keys, fingerings, etc.