Not thinking relativistically
It's an event that's separated from us in space-time by 3.9 billion light-years, before the radiation from it reached us it hadn't happened for us. Not meaningful to talk about how long ago it happened as something apart from how far away it is, space and time are one thing. Hard to wrap your mind around, which is why they say few people really understand relativity - our language is really not equipped to talk about events over relativistic distances.
On Earth, we can talk about two things happening simultaneously in different places and it has meaning because we have a fixed frame of reference - the planet itself. Over interstellar distances it's not meaningful - there is no fixed frame of reference, since space-time bends. Thus it means nothing to talk about when something light-years away really happened.
