@irontoenail - Your teacher was probably thinking in the long run, if he was going to try and make a classical musician out of you. That's unlikely to happen now if you've left high school.
There's no reason that you can't play the violin now, rather than the viola. Since there aren't that many viola solos, you might be better off with the violin as you'll be able to play solo pieces of music at home (or in a studio at least) that sound good by themselves, rather than ones that only sound complete with a group.
But listen to some violin and viola music online and see which you prefer.
I think learning a musical instrument is a very worthy pursuit later in life but you should do something that you'll enjoy.