Has anyone found out they got pregnant later in their cycle?

I've always had a regular cycle, at least over this last year it started around 25-26 days now around 27. I honestly don't no when I'm normally fertile as it used to be around 12-14 days after my period started years ago but at that time my cycles were around 30 days. I assumed that if my boyfriend and I slept together unprotected about 5-6 days before my period was due then we'd be fine. But I expected my period around Thursday and it hasn't come yet. However I then thought about the fact that my period did happen to be irregular last month where it came on time but was very light for days and lasted for about 7 days where normally it's only 5 days and not light except the first day. So im just wondering if perhaps it's just going to be late... There would be no sense in my taking a pregnancy test right now since it's only been 8 days sense sleeping with my boyfriend and also because the chances would seem to be pretty low getting pregnant that late in my cycle? I was just curious what everyone's thoughts are in this or if it's possible to get pregnant that late in a cycle that is around 25-27 days?