Before partaking of the Forbidden Fruit , they ( Adam and Eve) were immortal . They were told that on the DAY that they partook of that Fruit, they would surely die. Satan said they would not. They became mortal living a lot longer than us , and not one of them lived to be a Thousand , making one presume that the Lords Day was a Thousand Years , at that time. The Fact that Cherubim with Flaming Swords were placed at the entrance to make sure they stayed out of the Garden ( Sanctuary) meant the Garden was a separate basically impenetrable place, closed from the Rest of The Earth. As there was really no time in the Garden  , being Immortal , That would explain all the things happening on the rest of the Planet , Dinosaurs  etc. My Explanation  to make sense of things, for what it is Worth.