Age calculation problem

Zodiac belongs not to the solar or lunar calendar, but to the days in beginning of spring. February 4th in the Gregorian calendar is beginning of spring, which means you are an ox. If you were born after February 4th, you belong to the tiger. When beginning of spring was born depends on the specific meeting time of the zodiac on February 4, 1986, which varies from year to year.

Usually, for the sake of simple calculation, people calculate according to the year of New Year's Eve. If you name yourself after your birth date or tell your fortune, the fortune teller will also tell you that you are an ox.

As for one year old and nominal age, one year old is born at zero, and the first anniversary of birth is one year old. One year old in vain, two years old on the first anniversary of birth.