I was decent when I was younger (started when I was 6 or 7) but I broke my wrist some years ago and never found it comfortable to play since then.
with fretted instruments you can always pick it up and make a tolerable sound, even if you know nothing about music. when you first pick up a violin it will sound *vile*. really. and unless you have a mute, they're loud too.

but if you're really committed, then it is indeed a potentially beautiful instrument.
you're definitely going to want lessons too, it's very easy to pick up nasty habits. and a good violin is not cheap by any stretch

buy a student violin to start with, and if in a few months you still find yourself really passionate about it then maybe splash out on something a little bit nicer. also note that the bow has a profound effect on the feel and sound of your tone; you need to have a decent bow if you're getting a decent violin.
and one more point. if you've got "bass fingers" like me (strong and chunky

) then you might consider the viola, or even the cello, as they're a little bit easier to intonate for a bass player. you're definitely going to want a full size either way.
anyway, just my 2 pennies, good luck, and let us know how it goes =]
