I didn't have any doubts about my choice of career, but I had constant doubts about my ability, yes.
“The more tranquil a man becomes, the greater is his success, his influence, his power for good. Calmness of mind is one of the beautiful jewels of wisdom.”
“Discrimination due to age is one of the great tragedies of modern life. The desire to work and be useful is what makes life worth living, and to be told your efforts are not needed because you are the wrong age is a crime.”