First month, first negative

Tiff • Baby number 2 is on the way.
So this is my first month ttc and I'm now 3 days away from AF! I decided to be very inpatient and tested 2 days ago where I got my first bfn- 5 days to early do you think? Perhaps as I'm unsure to the length of my cycle. Usually it's around 30 days. Has anyone else tested with a first response test this early and received a bfn- was it to early or realy just truth? :(