It’s certainly hard for us to conceive or explain, but I don’t think it’s ridiculous.
Even physics (since Einstein) agrees that time is contingent – if the Big Bang cosmology is correct, spacetime as we know it “started” then. Time is not just the unchanging background reality upon which things happen – time itself came into existence and could very well pass from existence.
Those of us who believe in God as Creator believe that He created the entire universe, including space and time themselves. Thus, hard as it is for us to imagine, His own existence is not limited by time and space. We therefore say, with some imprecision, that God is “outside” of time. When we speak of God, eternity does not mean an infinite piling up of seconds and minutes and hours and days, but the alternate definition of “a state to which time has no application.”