Hi... I'm new to Maya, and this is the first time i'm going to post an answer (I've found your dilemma to be really interesting). What you point out is true... the time you need to learn said program is enormous. I have only just started, and am gobbling up all the info i find, and even so, the amount of knowledge you need to achieve something decent is overwhelming... there is loads of competition out there.
I'm 22, a Media Studies student at university, and have discovered recently a passion for this program. Like you say, it may take me 10 years to be good at it, but I know it's something that I really enjoy (don't think i'd get much kick out of being a doctor), and I'd love to have a job where I could channel my creativity through 3D.
My opinion isn't very valuable, I'm only a newbie, but I would recommend you to try it a little more, do some tutorials to get a hang of the basic tools, and see if you find yourself at night trying to sleep...thinking about that damn "Maya"! Then I'm sure you'll know the answer.
Good luck whatever you decide.