For many instruments, lessons and learning to sight read are crucial. For guitar, lessons are important, but reading not so important. However, learning some music theory - scales, chord construction, etc. - would be helpful.
If you can learn a handful of chords, and learn to make chord changes smoothly and accurately, you can play so many folk, rock, and country songs that you'll have trouble remembering all the words...
(Voice of experience...)
Example: key of G - G, C, D; throw in Em and Am for good measure
Take It Easy, Tequila Sunrise, Lyin' Eyes - Eagles
Hang - Matchbox 20
Whiskey Bent and Hell Bound, OD'd in Denver, Family Tradition - Hank Jr.
Lucky Man - Emerson, Lake, and Palmer
Slowdown - Dierkes Bentley
Who'll Stop the Rain - CCR
Wrapped Around Your Finger - George Strait
etc.