When I was young my teachers were the old.
I gave up fire for form till I was cold.
I suffered like a metal being cast.
I went to school to age to learn the past.
Now when I am old my teachers are the young.
Frost on verse: “…it oftener comes to nothing in youth before experience has filled the mind with thought. It may be a big emotion then and yet finds nothing it can embody in.” 
 Frost forsook the fire of his youthful passion till he could put it in the proper form. See also:  Fire and Ice
What Fifty Said