I started learning violin, actually at age 18. I was a piano major in college and took this as a group class for Music Education.
I started private lessons at 29, a month before I turned 30. I've had 3 private teachers and one of them for about 2 years, for a total of 2 full years, with summer classes.
I've seen people play violin and come across beginners online. It was very easy in college, and I did better than most people. However, I think I may have somehow damaged the nerves in my hands and arms since, if not at all before.