There was no central location. As far as anyone can tell, the universe was always infinite and has been expanding at every point for all time. It's pretty hard

There was no central location. As far as anyone can tell, the universe was always infinite and has been expanding at every point for all time. It's pretty hard to wrap your head around. References to sizes are probably the size of the "observable universe", which is basically the parts from which light is able to reach Earth. It might help to think of those more as ways to measure the expansion than the size of any actual object.