Dowe know our psition within the observable universe?

First off, keep in mind the observable universe is not the same as the entire universe. The observable universe is merely everything we can (potentially) see. We of course have to be at the center of the observable universe. It's not like we can see farther in one direction than another. However, there is a mathematical definition which defines the boundary of the observable universe. We need this, because while it is theoretically possible to see to the edge of the observable universe, in practice this is kind of hard to do. We've seen close to it, but it's pretty darn hard to find something right on the edge of it. So we define it mathematically as the farthest point from us that a photon could have reached us since the beginning of the universe. Keep in mind though, because of dark energy and the expansion of the universe, that point is farther away than 13.7 billion light years. This is a big misunderstanding people often have. If you want to read up on it more, the edge of the observable universe is known as the particle horizon.