How late can you implant??

How late can you implant? I'm 11dpo today and had some light cramping this morning. I had mild cramping for 2 solid days last cycle when I was 5 and 6dpo and thought for sure it was that. I had 2 vvfl idk if that is considered false positives? Anyways wondering if maybe I could be implanting? Af due Wednesday or Thursday.