While these questions have similar qualities, they are vastly different. A child can begin to be around and be familiar with music at a different age than actually starting music lessons.
So, for becoming familiar with music: this stage can be started as early as desired. Studies have shown that listening to classical music at an early age does wonders for the child's development process. From playing classical c.d.s around the house to introducing a young toddler to basic rhythms, claps, and basic instruments (Triangle, play set of drums, makeshift set of drums), providing a musically supplemented environment for young children is a GREAT idea. Classical music as opposed to hard rock music, has been scientifically proven to stimulate the processes of humans' brains. Therefore, if classical is played at an early age, not only will it introduce your child to the wonders of music, but it also may have a positive effect on their physical development.
As for starting music lessons: Many different music instructors possess different theories about what an appropriate age is for children to start music lessons. A music instructor that I know, believes that a good age to start is around 2nd or 3rd grade, or when the child can read fairly competently. Other music instructors I know have students who are as young as 3 or 4 years old.
I believe that it highly depends on the musical instrument, and the individual teacher's teaching style. For example: Choir or anything in a group setting is fine for younger children.
A child should definitely know their A-B-Cs & 1-2-3s before beginning music lessons and should be able to carry on a simple conversation and understand uncomplicated questions.
The problem is these requirements as listed above, varies for each child. That is why it is hard to estimate a specific age at which is appropriate to start music lessons. Once a child has met these standards, I believe that they are ready to start lessons. However, the parents need to be involved in their practice time and lessons, especially for youngsters in the age range of 3-7, and even up until the age of 10.
A decision to begin music lessons for children is highly dependent on the parents' priorities and desires. However, they must keep in mind that the child cannot go at it alone. Parental involvement is essential not only at lessons but also at home during practice time.
So does age matter? For music lessons, yes. For becoming familiar with music and melodies, no.
