The word infinity comes from the Latin infinitas or "unboundedness."
And in mathematics, infinity is an unbounded quantity that is greater than every real number.
Eternity or infinite time is time without end, without boundary. Time counts, but without end.
Time is geometric. In our perceptible universe, there are four dimensions, three of space and one of time. But there may likely be additional dimensions, either spatial or temporal.
Moreover, space/time is part of the Creation and not a property of the Creator.
Therefore, the term timeless would be more appropriate in meditating on God the Creator.
Or as a physicist around here grudgingly admitted after observing that there had to be a beginning of real space and real time for there to be any causality at all - existence exists LOL!
In Nicholas of Cusa's day most everyone believed in a steady state universe. Indeed, the insight that there was a real beginning of space and time came from the measurement of cosmic microwave background radiation in the 1960's. It was the most theological statement ever to come out of science.
A Name of God is I AM.
His Names are also Alpha and Omega. Jesus Christ is the First Cause and the Final Cause of "all that there is."
Was anything or anyone, before Christ, a firstborn creature?
Eternity or infinite time is time without end, without boundary. Time counts, but without end.
There are no "real numbers" in infinity, because every "number" has the same value. Thus, there is unity in infinity. Time, also, has little value in infinity, because time is a measure of change and there is no change in infinity. All points are the same.
That's enough thinking for the day. Thanks for giving me a headache!
Regards