I started bass at around age 22. I'm 27 now and can outplay many pros (though at this time I don't play quite as clean/precise as a real pro would, which is indeed a detriment, and only people equally [bleep]ed are willing to cooperate with me; you don't want me to help you with your album unless it's bizarre crap that normal humans will find intolerable), with a 5-string fretless as my main rig.

I just started guitar in January of this year and can solo out of thin air (as in, nobody wrote it, I didn't write it, I'm just playing it as fast as I think it up) until the cows come home... though only with bass techniques (as far as the left hand goes). I have yet to learn the stuff that can't be done on a bass but that can be done on a guitar. (Ehhhh... that goes vice-versa, too. :p ) Also, I'm nothing but ear; I don't know theory for [bleep]. On bass I can accompany anyone/anything at any time and can improv like mad until the neck breaks off... hardest part is not getting carried away... pro drummers have gotten mad at me a few times because I have a tendency to throw them off by doing weird stuff they don't anticipate... but ask me to even recite the notes on the fretboard and I'll be like "derrrrrrrr... hold on... uhhhh... B... C... C#... D... then up one is E...."

Go for originality. I don't mean you have to come up with an album of original material... but develop your own unique style, even if you only play other people's stuff. I've known too many pro and semi-pro players who can play just like SRV or Clapton or you-name-it (close your eyes and it's like SRV has risen from the grave) but don't have their own voice.