The term 'CERTAIN AGE' can be broken down into three crossword solutions: TEEN (4 letters), OFA (3 letters), and IRON (4 letters). TEEN is an abbreviation for teenager, which is a person between the ages of 13 and 19. OFA stands for Old-Age Security, which is a Canadian government program that provides financial assistance to people over the age of 65. IRON is a reference to the IRON Age, which is a period in human history that began around 1200 BC and ended with the beginning of the Industrial Revolution in the 1700s.