How old was Cao Cao's divination?

2 18 He is only eight or nine years old ~ ~ ~

Guan Ju: A warlock in the Three Kingdoms period, who was ugly, rude, addicted to alcohol and unpredictable in speech. Everyone loves him, but doesn't respect him. I like looking up at the stars since I was a child. Every time I play games with children and draw astronomy on the ground, people sigh as wizards. As an adult, he is well-known for his mastery of Zhouyi, Feng Jiao and Zhanxiang.