Every comment I have read seem to state some aspect of the truth. But we are like the blind men describing the part of the elephant we touch. That being said, I offer my part as a blind man touching another part of the elephant of time.
Time and space are considered to be the same thing. This is why it is called the space-time continuum. Time is measured by motion. Hence, when an object nears the event horizon of a black hole, time stops because the gravitational force of the black hole is so strong that all movement stops. Likewise if two identical clocks are used to measure time on Earth, one clock being at sea level and the other clock on the highest mountain, the clock at sea level will run slower than the clock on the mountain since the force of gravity is greater at sea level than on the mountain. That being said, that does not mean time does not exist, it simply means that the measurement of time depends on motion.
Regarding time in heaven, it depends on what heaven is, and only those in heaven may know. In my view, the creation is one. That means heaven is part of the created universe, thus part of the space time continuum. I see heaven as another dimension that we can not perceive of this same physical world, although it is not physical but spiritual, whatever that really means. So I think time exists in heaven as well.
Regarding God, I believe God is outside the creation, therefore does not live in time, although he does through his Son who became part of the creation. When we told that we will have eternal life, I understand that to mean we have the very life of God in us who is eternity. I define eternity as no beginning nor end since it is not part of time. As created beings we have his eternal life is in us, but our created lives is an everlasting life, which I mean is life with a beginning but no end.
I merely offer this a food for thought.