I'm not sure I quite understand how the timelines of Looper work.

You have the initial timeline (A), where Joe shoots himself, goes on to party, and then meets the Asian woman.  The Rain Maker starts closing all of the loops.  Joe (A) ends up killing the people that have him, and sends himself back in time and prevents his younger self killing him.

We find out that whatever happens to the young Joe (B) happens to older Joe (A).  However, this doesn't quite make sense since the timeline seems to have already been disturbed drastically by Joe (A) not being killed.

So, how is the timeline supposed to work in Looper?