It wasn't me that first mentioned the centre. I was curious about what he meant. Large in what sense? What do you mean by an end?
This sort of idea usually presumes a topography that we don't know. For example it could be that the universe is not a contiguous volume but rather multiple regions that are sparsely connected. It might not have an end. For one example: if you travel on the surface of our planet there is no end. So knowing the planet's size doesn't help you with the location of the centre on the surface. It may be that there is some cultural centre or some origin point for some species but it doesn't have a centre from it's topography. Also the surface of our planet is a Non-Euclidian space on the scale of the planet. But locally it very closely approximates a Euclidian space for us. It may be the reverse with the universe.