Which is the oldest galaxy?
The oldest known galaxy is GN-z11. It is often reported that this galaxy is 13.4 billion light-years away, but the reality is more complicated. We are seeing it today as it was 13.4 billion years ago, as the light from GN-z11 has taken this long to reach us. This implies that GN-z11 is 13.4 billion light-years away, but you have to remember that the entire Universe has been expanding the whole time that the light has been traveling.
The actual distance to GN-z11 now is currently 32 billion light-years. This is called its "proper distance".
13.4 billion years ago, when the light that we now see left GN-z11, it was only 2.66 billion light-years from the Milky Way.