I Am the Protagonist

In his twenties, after experiencing all the disappointments, he felt in the infinite loneliness that the past twenty years were just a mirror image, and he felt things that he had never felt before. When he made up his mind to change, he went back to the past for no reason. When he was about to enter elementary school, everything returned to the original point. Can anything be changed? This novel and its characters are purely fictitious. Any similarity is purely coincidental and should not be imitated.