Oldest Milky Way star

Only 500 million years after the Big Bang, a star was born that would later be part of globular cluster NGC 6397, 7200 light years from Earth, which contains of around 400 000 stars. This star, perhaps not the oldest in the galaxy, is the oldest one so far observed in the Milky Way galaxy: about 13.2 billion years old. That's January 14th for those following the Cosmic Calendar. Celebrate the birth of this early-starting star, HE 1523-0901, by getting up just after dawn on Monday.

Note that the galaxy itself didn't start to form from these early stars (and various other bits and bobs) until between 6.5 and 10.1 billion years ago - no earlier than April 6th in our Cosmic Calendar.

I would like to appeal to any experts or students in astrophysics or cosmic evolution to help me populate this sparse end of the Cosmic Calendar with interesting events in the early universe. For now, I'm digging up the occasional tidbit from Wikipedia with my own meagre understanding of the cosmos - a more systematic set of dates would be very welcome.