Because it isn’t a computer program that will end exactly in 21 days 13 hours and 10 sec 😊
I don’t know if you understand me lol 😄. It’s mostly an Indica dominant, Indica’s flowering period is short, around 55 days to 60 days and sometimes for the longest one around 65 days to 70 days, it isn’t an exact science bro. But for sure, yours is nearly done, perhaps another 2 weeks more.