It means that If we looked at this 31 years ago, it wouldn't be a block hole yet. If you were to transport yourself there at 50,000,000 times the speed of light

It means that If we looked at this 31 years ago, it wouldn't be a block hole yet. If you were to transport yourself there at 50,000,000 times the speed of light (eg. in a relative instant), you would find it much older than we perceive it now.