We know at the very least that this predestination means that anybody/all that were going to be received into the eternal life to come was going to have to come to it through the adoption of Christ. Whether this means I or you specifically were chosen/singled out beforehand is not suggested by the language here but, may be quiet possible. The later may but a debatable point, not the former. Let us start off by what we know.
If this were to mean singled out beforehand, it could just as well mean that those specifically who first believed (early church, disciples) were singled out and not necessarily the rest of us who believed because of their testimony. Jesus for instance chose Peter at the shoreline and may have chosen him before even creation. This is not to disregard the predestination of all but to confirm at least this much.