Was Christ premature baby

Why do we have to do everything at the same time.
Why do we have to do shopping in supermarkets on weekends.
Why do we have to go to work at the same time.
Why do we need to have to celebrate Christmas at the same time, which is wrong anyway. Christ was not born on 25 of December, but on 1 January. If he had been born on 25 December, then the calendar would have started from that day, and 25 December would have become 1 of January (because our calendar is „before Christ, BC or after Christ, anno domini, AD”). Christ is a premature infant, because he was born before his birthdate.
But whenever Christ was born, Merry Christmas everyone.