Owner of RDL Strings
A brief bit of wisdom from 23 years experience.
After 23 years watching children take lessons on violin, viola, and cello, I've reached some conclusions:
The violin is not an instrument you can "pick up" on your own.
Without professional instruction, odds are very poor you will learn to play. Intuition tells most parents to let the child "try it" the first year and, if they remain interested, lessons will be provided at some later date. This never works. Bad habits are ingrained in that first year. Odds are, without lessons, they'll quit before the first year is up.
So give your child a chance for success. Begin lessons at the beginning. I promise you this will work.