According to my understanding of the theory of the Big Bang, it was the beginning of the universe.
In other words, the material that caused the Gamma Ray Burst had to originate at the same moment of time as the material that composes our galaxy and solar system.

I was just thinking that if the universe is 14 billion years old and the “burst event” happened 7.5 billion years ago, then the universe had only had time to expand for a period of 6.5 billion years before the “event” happened.

What puzzles me is; if the universe was only 6.5 billion years old when the event happened, then how come the light took 7.5 billion years to reach us.