If we suppose that something always existed, than to prove that something always existed we would need t demonstrate a thing existing always. The paradox than arises, that you can not demonstrate that something will always exist, as it would require an infinite and ever increasing amount of time. This means that, in this case eternity or immortality is non-demonstrable. To see this clearly, ask an immortal if they have lived forever? Not True.
Again, we might think or deduce that either:
1. Something came from something.
2. Something came from nothing.
In each case, if you bring them to their logical ends, 3. 0>something>0 can still be used as causation loop, just as (2 ) something>something. In either case it is probable that both 1 & 3 are possible, but there can still be 0>something>0 wherein there is no causation chain as in 3.
The probabilities work out amongst the three that 66/33 that the universe is perpetual, meaning infinite in both directions. True.
We look at what we can deduce from something and nothing as energy states:
1. Conservation of energy - No loss or gain, transformation.
2. The impossibility of absolute zero.
3. Infinite singularities.
4. Maximum entropy.
One, two, three, confirm perpetuity, and 3 annuls 4. According to this evidence it is 75% eternal. True.
There are conclusions that come from this, that you might find with your own reasoning.
One question might appear for example: Which is greater, variation or time?