Birth of Buddha

The story of the birth of prince Siddhartha tells us that he walked and talked right after birth. That he even said that he will become a Buddha in this life and end the cycle of life. But after this he seems to have forgotten what he knew about being a Buddha even on the day he left the palace to find the truth. He started off knowing he would become Buddha, then becomes very confused with all the life experiences as a prince and has no idea what to do or that becoming a Buddha is the answer to it. How is this possible? Is it a flaw in the story or is my understanding of the question poor?