Accurately speaking, there was never a beginning–just a breath, but for the sake of the human mind, which cannot grasp the concept of forever, there has to be a beginning and a point in Time. When that time was cannot be calculated and is beyond human comprehension.
To assist in the understanding of the following concepts I have prepared an illustration.
The third heaven, or the heaven of heavens, always was. It is the central sphere of Light from which all things were created, and that is God. The Bible refers to it as the throne of God.
“The depth” or “the deep” mentioned in the Bible is the universe; the Bible also refers to this as the sea. It too always was, as it is situated within the central sphere of heaven and is the deepest, darkest and coldest part of God. It is our space.