What was the latest you tested positive for the first time ?

I quit taking the pill since 10th of september. I have been on it for 11 years. Af should have started a week ago on the 13th. 
Still nothing, just now and then some cramping but nothing like it would if AF would start. 
Friday was the last time i tested and i got a BFN.
I know my AF can be late because i just stopped taking the pill but i'm just wondering what was the latest you got your first positive test ?
I still have a little hope it might turn into a positive.
My SO and i BD every other day throug out almost the whole month and every day what should have been my fertile week.