4 1 year. According to China's goal, the standard is: going to kindergarten at the age of 3; Go to primary school at the age of 6; Junior high school 12 years old; 15 years old attending high school; 18 years old went to college, 18 years old went to college in 2000. It has been 23 years since 2023, and 18 plus 23 equals 4 1. It is concluded that the age of going to college in 2000 should be 4 1 year.