We have a tremendous amount of raw information flowing through our brains 24/7 from before we are born, from the external world through all our senses and from within our minds as it attempts to make sense of that information, make predictions, generally reason about our existence, hallucinate alternative realities, etc. etc.

If you were able to somehow capture all that information in full detail as you've had access to by the age of say 25, it would likely dwarf the amount of information in millions of books by several orders of magnitude.

When you are 25 years old and are presented a strange looking ball and told to throw it into a strange looking basket for the first time. You are relying on an unfathomable amount of information turned into knowledge and countless prior experiments that you've accumulated/exercised to that point relating to the way your body and the world works.