I started at age 17, never took lessons nor bothered with theory
... which I later regretted

I forced myself to forget all I knew 2 years ago and started all over again - this time the correct way thanks-to-guitartricks-and-many-others. I am now 26 and playing the blues.

I bet you opened this thread because you're wondering whether or not you suck for the time you've been playing so... here it is. I guess whatever age you start playing or how long you've been playing is irrelevant. It's a matter of how seriously you learn the guitar (and music). Learn the chords, learn the major scales. These are the most important concepts to understand for everything else in occidental music.