Found my admission letter from 20 years ago while cleaning! My past dreams!

Forty years of arduous study
Midnight oil burning at five bells
Through countless hardships, achieving the exam's success
Determined to enter the capital city
Looking at the sick relatives before the door
Seeing one's own coarse clothes
Without a single piece of scholarship
Roaring towards the sky in the emptiness
Who knows the pain in one's heart
The past is irretrievable
Though diligently refining gold, it's only after exhausting all the yellow sand that gold appears