With some of these questions you could say we have working assumptions rather than absolute knowledge. To have an edge there would , I think, have to something that wasn't universe but the universe seems like all the space/time there is.

Though we don't know for sure , there is some reason for thinking it might also be infinite in size. There is in edge in the sense of the limit of our ability to observe. The observable universe has for us increased in size as telescopes get better though you could say that its also a sort of illusion since the further we look , the further back in the universe's history we are seeing. We are seeing it as was. We can only see as far as light has had time to travel. The limit is called the cosmic horizon.

And we also have some reason to think its pretty much the same everywhere in general. Though some bits are clumping together the space between is increasing everwhere. At one point in the past it infected very fast , slowed down and is now accelerating again. But as far as we know whereever you were in the universe you would look out and observe something similar to another observer. If the universe continue expanding its possible that we could imagine one day an observer looks out and sees nothing because all the stars would be too far away for light to reach them.