I was personally exposed to music at a very very young age. My mom started me on piano and violin when I was 3 years old. I grew up with music (both my parents are musicians and my brother does music professionally) and I feel the fact that I grew up surrounded by music at a young age shaped who I am today and gave me an outlet for expression at a very young age. Especially if the child is intrestedinterested you should definitlydefinitely start the child at a young age. Then, if they don't enjoy it, you can rethink your decision but for now you should expose them them music. I think having music with me from such a young age gave me a life long skill that I am sure your child will love.