this sounds purely philosophical and i'm really uncomfortable somebody make him stop he's going too deep
It is a philosophical point.
It's late and I can't remember all the terminology from my philosophy lectures two years ago, but I think one answer is that while time is infinite, it has a beginning.
We can consider it infinite in the same way that I can add to infinity.
I start at zero, and I keep adding by one. I will go on and on and on, because there's no end to numbers.
But I can still say at any one point that I am at the present, because I can see how far I have come from the beginning (in terms of time, the beginning is the Big Bang). As such, with a constant landmark on this infinite line that is time, I can identify my present in relation to the beginning, even though there is no end.
So, basically, it would suggest that time came into existence at the Big Bang.
There was no time before that.
It's difficult to comprehend of course, because we have no understood concept of there not being time.