My daughter asked me this - she's almost 7. I started when she was about 3. To her, she has no memory of not having a mother who plays the violin.
One time, when my daughter was about 4, I left a can of bug spray by my violin. That was not smart. She pressed the button and covered the varnish with hundreds of little spray marks. I discovered it way too late to save the varnish.
In my first few weeks of playing, I distinctly remember feeling dizzy and sometimes even a bit nauseous from the strain of standing for long periods of time with my arms held aloft (25 whole minutes), struggling to concentrate on a thousand different things that all felt like patting my head and rubbing my stomach. It felt impossible to focus on any one aspect of the physical or mental experience for long. When I did manage to focus on something, I completely lost the ability to maintain awareness of anything else.
I don't know exactly when I began to feel guilty and stupid for wanting to pursue something purely for my own enrichment. But I knew I had to fix that.
There are a lot of Why's to explore within myself. Why Violin? Why Now? Why Write about and share it? Why add something like this to my plate?