In mathematics, in straight line situations, the concept of infinity works both ways; no beginning and no end.
When you think about it, time is a man created concept that makes sense; it's a past and future straight line situation with no plausable beginning or end. So far as math and science is concerned, time is eternal.
Seems to me that eternity can be many things. Just my own limited musings but eternity can be spatial in relation to scale, not just time. I’ve wondered in the past just how final the last second of life and consciousness in human form might be, applying scale to linear time. A second, a half second, a quarter, an eighth, a sixteenth... there’s not really an end there. Finality is an illusion.
“So far as math and science is concerned, time is eternal.”
Exactly, but math and science were both created by God and therefore, He is not bound by either of them, so they are insufficient tools for us to try to draw conclusions when it comes to Him. You might as well try to count the stars in the sky with an abacus.