How long?

I was wondering if anyone knows how long it would normally take to get a BFP after IB? I am convinced that's what I had on the 4th and 6 days later I tested and got a BFN. No AF yet, I have a few more days until it should come. If I was preggo, would 6 days past IB be too soon to test?! The IB was barely even there and extremely pink. I noticed it while using the bathroom and then it was gone as fast as It came. Not enough to even use a panty liner. Any ideas?