Ability, experience and books have solution for all the problems.
Compromise brings harmony to both, happiness to none.
Your youth is certainly finished and old age has definitely arrived if you feel that you are losing enthusiasm, excitement and energy towards your dreams and goals.
Between natural ability and education choose natural ability, as it will keep you happy and will fetch you the glory sooner.
As for Doing-good, that is one of the professions which are full. Moreover, I have tried it fairly, and, strange as it may seem, am satisfied that it does not agree with my constitution. Probably I should not consciously and deliberately forsake my particular calling to do the good which society demands of me, to save the universe from annihilation; and I believe that a like but infinitely greater steadfastness elsewhere is all that now preserves it.