@Metal-Brain
The universe is a hard thing to grasp, because it is "everything," and is not properly regarded as being situated in some "bigger" space.
Knocking the number of spatial dimensions down from 3 to 2, we could simplistically envision representing the universe as bits of matter stuck to the surface of an expanding sphere (like a balloon). The sphere starts as a point (radius zero), and then, as it grows, the space between the bits of matter increases. Indeed, every point on the surface of the sphere (our "space" ) increases its distance from every other point. In this sense "new" space is being created (by dint of the surface area of the sphere increasing). Where's the center of this universe? Well, there is none. No point on the sphere is the point where the expansion began.
And the expansion of space is not limited by the speed of light. The speed of light holds
within space, and does not apply to space itself. Nothing in our expanding universe, as far as we know, is moving
through space at more than the speed of light. Space is not modeled as traveling through any kind of medium forming a "bigger" space.
As for the age and size of the universe, it is ultimately only guessed at based on the available evidence. It could be infinite large and infinitely old, and some theoreticians are still working on ways to make that work with the cosmic microwave background's observed properties.