Question: 16 days dpo, 3 days late, but negative pregnancy tests?

TTC. I am 16 dpo, AF is 3 days late, I have taken 3 pregnancy test in the morning and they all came back negative. I have a 32 day avg cycle. I am just wondering how late implantation can happen?

I am probably being to hopeful that there is a baby, but its probably just a late period, right?