How big is the universe?

[Anomalocaris]

Sure!

Do you remember the user  StatlerWaldorf who was around a few years ago. He always advertised this ingenious creationist cosmology based on the ambiguity how clocks are synchronized in relativity. You can consistently use a convention in which light travelling towards the earth has infinite speed, and away from earth has half of what we perceive as the speed of light. This is completely unfalsifiable because it is a self-consistent relabeling of everything that doesn't change any measurable physics. It has as a consequence that what we see in the far reaches of the universe actually happens at this very moment. This way, some smart creationists wanted to justify why we can see far away Galaxies even if the universe is only 6000 years old. It's very implausible for a whole list of reasons though.

I would think that the Earth could be said to be at the subjective center of an infinite universe, though not for any reason that supports creationism. In an infinite universe, wherever you are at any point is the center because there's no circumference and there will always be the same amount of space all around you.

Wrong.   I am the subjective center of the universe.   Earth merely knows which side of its crust is buttered and sticks close to me.