Actually that’s not true.
It hasn’t changed much since humans first started to keep track, but it was not always so.
——>It hasn’t changed much since humans first started to keep track, but it was not always so.
Yes it has. The seven day week and 30 day month cycles were established at creation. I would invite you to read the account of the flood in Gen 7 and 8. That’s about 1500 years after the flood. Note the specific timeframes mentioned. There has been no change from creation to now.