A very odd question for this group, and perhaps one which doesn't seem
relevant to the discussion at first, but please humor me for just a
moment...

We all know that the great masters of classical music; Mozart, Beethoven,
Mendelssohn, etc., were instructed in music from an early age, and
henceforth, were well fluent in musicianship and composition by their
teens.  My question is, is it possible for a layman, well into his teens,
who is highly musical, but not learned in the technical aspects, to take
on the arduous task of learning an instrument and embarking on structured
compositions when in his childhood he has only worked on little melodies
and unrelated tunes in a haphazard fashion?

How old is too old to become a virtuoso?  I can't think of one example
of a late-blooming classical composer.  If any of you can think of some,
I'd love to hear them.  It would give me great encouragement!  Thanks,
and happy listening!

 ---Barrett Reynolds