infancy vs preadolescence

infancy

noun
  • The earliest period of childhood (crawling rather than walking). 

  • An early stage in the development of anything. 

  • The state of being a minor. 

  • The state of being an infant. 

preadolescence

noun
  • The period between childhood and adolescence, between the ages of about 9 and 11 for girls, and 10 and 12 for boys. 

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