Hi there. I am another adult beginner who has been playing for a few years. I first took up the violin as a young adult in my 20s. I set it aside 2.5 years later when I went back to college. 25 years later, I took it up again. That was about four years ago.
Most of the music that I play is church music, as our church has a very welcoming and challenging choir director who has gotten me over most of the stage fright that plagued me in my youth. For fun, I like to chew on music that is too difficult for me, a few measures at a time.
I have played around with the viola as well, and am still considering buying one. But I don't think I will give up my violin for it.