It is my opinion that no girl who wishes to keep her voice in the prime
of condition all the time in after years should start to study much
earlier than seventeen or eighteen years of age. In the case of a man I
do not believe that he should start until he is past twenty or even
twenty-two. I know that this is contrary to what many singers think, but
the period of mutation in both sexes is a much slower process than most
teachers realize, and I have given this matter a great deal of serious
thought.