Cd 36 21dpo

KLS • 💙💙Baby Boy due 8.17.18💙 R.C.S Born 8.4.18💙
Should I not be able to get a bfp by now? Af is 5 days late, due the 20th. Last three cycle have been 30 days. Wtf. Why can some people test early and some have to wait to cd40?