Looks like my original reply didn't go as expected.
To your question about limitations - use what you have! Many
replies have been about woodworkers (Krenov, Maloof) who are
still creative into their 80's. I think Sam has enough wood
collected to last him several more lifetimes. But the thing
is from what I gather is that they are still enthusiastic
My wife's grandfather was active in woodworking to the
end of his life (91). He made things for his grandchildren,
while not artistic, were certainly labors of love. Everytime
I see the pedestals he made, I think of him and hope I'm
as good as he was.
I'd say, you will always be in learning mode whether or
not you're 25, 45 or 75. There's enough headscratching
exercises in woodworking that it should keep a person
mentally healthly, which I understand is a crucial as
we "age". I won't worry about achieving a specific level
of "success". It will be whatever you reach and willing
to strive for.