well, in China,you can give the year of birth or the number,both okay.
usually,our age is 1 or 2 years oleder because we count our age according to lunar calendar。
when a baby is born,he or she is already 1 year old.and we add our years of ege every Spring Festival.
for axample, if you are born in December,then you are 1 year old right away. and if it is Spring Festival in 2 months, you will be 2 years old then.