my boy baby born on 9 month he is preterm or not date given is feb 20 but born on jan 20

A. hi the date which is estimated by your last period date,it is just tentative date it is not necessary to get delivery on same date because sometimes if someone is not sure about last period date, estimated date can be wrong there so counting can be wrong now if your child is happy healthy and active, weighs around 3 kg then no need to worry about such things