Finally, it would be silly to say that the Universe consisted of only what we could detect. Our ability to detect matter and energy is constantly improving, and in the end there are parts of the Universe we may never be able to observe but whose existence we may be able to infer indirectly. Those parts, too, belong to the Universe, even if we can't detect them directly. Still, one must begin somewhere. Infinity can apply to physical dimensions as well as time, and in the case of time can be partial instead of complete.
Infinity is a difficult and sometimes uncomfortable concept for many.
Religious teachings seem to handle the concept quite well, though, in describing supreme beings that have always been and always will be. In cosmology, the idea that, taken over large enough scales, the universe is roughly the same in any location. This is one of the key assumptions of cosmology and one half of the Cosmological Principle. And the Universe was also much smaller and denser in its past. That the universe has no edge.