As he spent all his time writing, Wu was unable to graduate from junior high. He was also unwilling to repeat a grade, so he had no choice but to enroll in a private high school that would accept him. Later, his brother sent him to Taipei to take the entrance exam for the more prestigious Shulin Senior High School in Taipei County.
耽溺文學的結果，吳晟國中未拿到畢業證書又不甘心留級，便以同等學力資格，勉強考上一所私立高中，後來又在大哥安排下到台北補習，考取了台北縣立樹林高中。