puerility vs youngness

puerility

noun
  • The state, quality, or condition of being childish or puerile. 

  • That which is puerile or childish; especially, an expression which is insipid or silly. 

youngness

noun
  • The state or qualities of being young or youthful; youth. 

How often have the words puerility and youngness occurred in a corpus of books? (source: Google Ngram Viewer )