Bass for only 21 months? You've been playing something else waaaaaaaayy longer. Looks good...!
I was a very BAD keyboard player... and an even worse guitar player. I could would out cowboy grip chords... that was about the extent of it.
Bass was the first instrument that I actually understand... and my wife lets me practice about 3 hours a day. I studied under Anthony Wellington and Scott Devine at Scott's Bass Lessons... and instead of learning songs, all I do it work theory and dexterity.
I also try to play with any band that will let me show up on a regular basis... it all helps!