It sounds like you’re asking about “coming of age” and the “key” idea together. In plain English, coming of age means reaching adulthood or becoming mature, and a key in this context often refers to the traditional “key of the door” given at a 21st birthday to symbolize responsibility and adulthood.

What it means

  • Coming of age = the transition from childhood to adulthood, or becoming more mature.
  • Key = a symbolic gift, especially in British tradition, that can mean the person is now trusted to have their own key and more independence.
  • Wooden key = in some newer or cultural gift versions, the key may be made of wood as a keepsake or ceremonial token, while still carrying the same meaning.

Simple example

If someone says, “I got a wooden coming-of-age key,” they usually mean they received a decorative gift marking a milestone birthday or adulthood, not an actual house key.

In short

The phrase is about growing up , and the key is a symbol of that milestone.