What we 'know' is given to us by the mathematical models which we invented to describe the observed reality.
Currently, we have different models to describe reality based on the scale of observation.... Which is interesting because as you zoom into the microcosmos there's a point were the laws of physics magically 'switch' from relativity to quantum mechanics.
As a programmer who is not a physicist, I can smell a hack right there. Which brings me to the inevitable conclusion that maybe our model of reality is not entirely correct.
So if I were to bet on weather time existed before our model's mathematical moment zero or that our mathematical model is imprecise, I would definitely choose the infinity of time.
Our mathematical model is for us or future generations to adjust to whatever we discover in the future.