Lord, you have been our dwelling place
in all generations
Before the mountains were brought forth,
or ever you had formed the earth and the world,
from everlasting to everlasting you are God.
~ Psalm 90:1-2
Our God is everlasting, eternal. Eternity is something hard for us to fathom. We are too bound and limited by time. I find the concept of time quite mysterious - I find that there are two possibilities. Either there is no present time, only past and present - the moment you think are at that present moment, it is gone, past and moving onto to future time that almost immediately become the past. Or there is not past or future, it is present, now.
As much as I don't even fully understand time let alone eternity, it would be an amazing thing when I am finally in God's eternal presence. I am not sure if God's eternity is temporal or nontemporal, though I am leaning more towards to former. But whatever it is, I am glad that God is eternal and is operating out of our limitations. He is from everlasting to everlasting God, no beginning and no end.