As a violinist of over 25 years, I would say you are never too old to learn an instrument. As a lifelong student, I would extend the thought by saying you are never too old to learn anything.
The importance for violin comes down to your level of resolve in learning a new technical and artistic skill. Are you willing to train your muscles to learn new positioning and movements that they've never done before? Are you willing to train your brain to learn a new way of thinking that it has never thought before? Are you willing to set aside a quality chunk of time every day dedicated to learning in these new aspects?
These are introspective queries that I think are important to consider before playing. But the simplest elements of the questions boil down to one question in summary - do you want to play?
