age and musical instrument

Is this correct and natural?

Age is of the predominant determinants that can impact on the process of learning a musical instrument. The younger a child is, the more conducive their brain is for learning a new musical instrument. Consequently, the sooner the process of learning is started, the better a child can learn how to play an instrument.

I don't care much for the first sentence. Perhaps:

Age is the primary determinant for how well a person can learn a musical instrument.

How about:

Age, above all else, determines the progress of learning a musical instrument.

Is this okay now?

Age is the primary determinant for how well a person can learn a musical instrument. The younger a child is, the more conducive their brain is for learning a new musical instrument. Consequently, the sooner the process of learning is started, the better a child can learn how to play an instrument.

Is conducive correct? What other options do I have?

It seems okay, but try:

The younger a child is the easier it is for him or her to learn a new instrument.

Age is the most important factor in learning a musical instrument.

"Conducive" is used to describe conditions rather than a part of the body. Perhaps you can say "The brain is most efficient in learning a musical instrument at a younger age".

The earlier a child starts learning to play a musical instrument, the better (and quicker they pick up).

I'd use efficient at.