But you could argue it is 'everywhere in the universe'.
Yes, you're exactly right. In the Big Bang model the universe has no center, no edge, and wherever you are in the universe, it appears like you're in the center. It is the "unbounded" solution of the GR equations used by cosmologists to describe the universe. The initial explosion doesn't occur in space, but creates it's own space as it expands.
The "bounded" solution is the one used by Russell Humphreys in his book "Starlight and Time". That universe does have a center and an edge. The initial explosion occurs in already-existing space and expands into it.
Both solutions are mathematically valid. The first one was chosen for a logical reason: galactic density is pretty much uniform no matter which direction we look, and in the first model that's true everywhere in the universe. In the second model it's only true if you're actually near the center.
Evidence of the second solution, the one used by Humphreys, would include the discovery of concentric shells of galaxies around us, in an effect called 'galactic redshift quantization'. This effect was claimed to be found in 1977 by Tifft, debunked, found again, debunked again, and found again, the latest time by John Hartnett. He actually got it published (!), believe it or not.
I know I'm being wordy, but I'm interested in this stuff and like talking about it.
hiscosmicgoldfish, if you're still following along, YEC Humphreys solves the old-starlight problem by using GR to actually stop time around the earth for billions of years, giving all that distant starlight time to get here. So he gets to have a young earth and an old universe simultaneously. Wild stuff.