We can't see the "edge" of the universe. So we have no idea. We don't even know if there is an edge.

Pretend the universe is a balloon. While it's deflated, using a marker, draw two dots on the balloon an inch apart. Now blow the balloon up. As you blow, the balloon is expanding. The two dots will get further and further apart. And yet they haven't actually moved.

Is there really an edge to the balloon? It's hard to say. In a way, the balloon is a two dimensional surface with no clear edge. But only when you look at it in 3 dimensions can you say there is an inside, an outside, and the balloon itself.

Well if the universe is a 3 dimensional balloon, there might not be an edge on 3D space, but if you were to look at the universe in 4D, there might be an inside, an outside, and the universe itself.