Watch the In Your Teens online guitar lesson by Corey Congilio from 50 Blues Rhythms You MUST Know
By now you should be well aware of the differences between 7th chords and 9th chords.
I think a natural progression is to move towards a 13th chord. As we learn more chords we must become cautious of when and where to use them. Like I said before, a 7th will always work where a 9 or 13 is called for.
However, we should know what these chords sound like. We may never have to play them but, why not have them available if need be.
Remember, I always say "think sound." What does the chord sound like? To me, a 13th chord sounds about as jazzy as you can get. 7th chords sound aggressive to me. 9th chords are funkier sounding.
Think of it however you like but, make that connection between your ear and mind. You'll never go wrong if you do. This 13th shape can be taken from the Colonel Chord we learned in #17. The 13th note is an F# that's often called an upper extension of the chord. F# is the sixth note of the A major scale. Play it up an octave and that is where the 13 sound comes from. As simple as that.
Pay attention to this number stuff. Chord tones and numbers become very useful down the road. For now, get your feet wet with a 13th chord.