Time varies with mass, acceleration, and gravity, but we shall not go into details. We note that the universe could also be finite, especially if it had a beginning, and only be infinite in the infinite future. Because it is apparently expanding at an accelerating speed greater than the speed of light, we can only see part of it, and as time goes on we will see less of it because the expansion will “outrun” light.
This does not contradict the idea that objects cannot go faster than the speed of light as the expansion is not to do with the objects in space but is due to the expansion of space itself. It’s like marks on a balloon that further separate from each other as the balloon is pumped up; the space between the marks expands. Nor does it depend on human minds for its existence, although it exists in human intellect.
We see then that although mathematics is a model for reality, it is not reality as we imagine but has a separate existence in the abstract: as already noted, infinity is a mathematical idea and not something that actually exists in real life. Similarly there is no single point corresponding to time zero, as a point is a mathematical construct of zero “length.”