Before our Big Bang there was no time, at least in our universe,
and we all felt our universe was all that there is.
Today almost all physicists think our universe is only one of perhaps trillions or more,
so yes time had to exits somewhere long before it existed here and
they think new universes are still being formed.
Think about it.
There is no telling how long time will exist somewhere.
If before BB was no space and was no time but was only MATTER . . . .
. . . then . . . in which structure the MATTER was existing?
In which structure the original universe was formed ?
Whatever structure it was, it wasn’t matter. Matter and time were created at the moment we call the “big bang”. I’m not a physicist so I can’t describe it using physics, but it was what we would call an uncaused cause. We are looking at that moment through the lens of a cause and affect universe. A different set of laws than the ones we normally interact with were operating on that. To us, it was nothing, non-matter, non-time. We don’t yet have the common language to describe it.