The traditional age in China is nominal age, which is calculated according to the lunar calendar. At birth, it is 1 year-old, and it increases by 1 year-old every Spring Festival. This year is 18 years old.
According to the Gregorian calendar, one year old is 0 years old, and every birthday is increased by 1 year old. Now it is 16 years old, and this year it is 17 years old in the solar calendar.