positive tests

Bree • Mommy to a 5 year old boy & due with boy number 2 in December 💙💙
How many dpo would you expect to see a positive test? Vfl included.. can you have completely negative tests and then a positive? I can't help but feel discouraged by all the vvvfl posts.. anyways. Just wondering what you gals think, how many dpo would you think you'd see a bfp