Final answer:
The given quote from The Analects by Confucius does not provide information about Icarus's age during the mythical event of his rage about living in a cave, as it pertains to Confucius's own life stages, not the Icarus myth.
Step-by-step explanation:
You asked how old Icarus was when he got into a rage about living in a cave. Unfortunately, the information provided from The Analects by Confucius does not pertain to Icarus or his age in the mythical story. In the Analects, Confucius speaks of his own development and understanding as he ages, which includes being bent on learning at fifteen, but this does not relate to the myth of Icarus.
The story of Icarus and Daedalus is a myth from ancient Greek mythology and the details of Icarus's age when he was confined with his father Daedalus are not specified in classical texts. Therefore, we cannot definitively answer your question without additional context from the specific version of the myth you are referring to.