How old was Sima Qian's first academic tour?

In Sima Qian's life, from the age of 2 to the age of 5, nearly one third of his life was spent traveling in the wild. At the age of 2, when he was in the prime of his life, he embraced the lofty aspiration of saving the world and calming the people. In order to have a real understanding of society, life and the rivers and mountains of the motherland, he began his first academic tour to show his feelings of climbing mountains and facing the water.