Thank you phinds for your very knowledgeable reply. Although I think my statement 'therefore I am confident that my planet is a little sphere surrounded by a massive sphere of space containing stars' is actually not incorrect. I did not say that the universe was a 3D sphere. In the context of...
The earth is a sphere. I can stand anywhere on its surface and look up directly above my head at the night sky and see lots of stars many light years away. I see this view wherever I stand on the earth's surface although the stars will be different ones, depending on where I'm standing...