In studying the Bible we have hints, evidence and proof. God mostly likes to work with evidence.
The phrase translated "Without form and void" indicates a period of time prior to creation week. With this and a few other phrases here and there, including in the writings of Mrs. White, we have at least hints, if not evidence that there was something here for Lucifer, the other angels and other worlds to do things to study out Lucifer's questions. We are not given details about this; but hints and evidence that point to this. Then when the two sides of the great controversy was formed, and when what ever was here turned into complete chaos; that is when the Spirit of God hovered over the chaos and said "Let there be light" both including the physical light; but also announcing that the universe was moving into a new age of learning light about God.
So we have an unknown period prior to those special 7 days. Another unknown period after the 7 days when Adam and Eve were working with the garden. Now the text is not as clear as we would like to whether or not Adam and Eve were physically distant or if he was there with her. Mrs. White draws lessons on the idea that they were distant. While she does warn us that her job is to make applications to us today and to NOT use her words for exegesis of the text; the idea of Adam standing there clueless through the conversation seems odd, so I lean in the direction that they has separated. But we have a second unknown leant of time.
A third unknown is the time from the fall to different times in history. We tend to read the genealogies through the eyes of western Greek eyes started centuries later. Ancient genealogies, even studies within the Bible, tends to first list the important people, and skip the less important. The text that made Genesis is so old and multi updating's in the language that it is difficult to translate the numbers. We tend to get from 6,000 to 10,000 years from these attempts. And often in history a first born child would be named after a paternal grandfather; and thus two names repeat over several generations, but we get one listing of each name in written genealogies. So we can't get much beyond saying that the earth is young enough for the memory of Adam and Eve and the people listed stayed in human memory. Elder Robert Pierson first wanted the church to become strong proponents of the 6,000 years, but even the theologians who were trying to apply his fundamentalist views had trouble, so he requested them to try not to get much beyond 10,000 to 12,000 years (When I was at the Seminary this conservative group was open to go as far back as 21,000 years).