“So, you don’t believe in infinity. You’ve answered one of my questions. Which leads me to ask the other question again: Didn’t it have to get up to speed at some point in time? Did it for some period of time get up to a higher speed before it slowed down again to its steady current rate? How do you know?”
The reason I know is that light has never been observed to go faster than C. There is no reason to believe that light was faster for some time before it slowed down to its steady current speed. And light would have to be traveling several orders of magnitude faster to cross 13.7 billion light years in 6,000 years. Some force would have to act on it to slow it down and it would have to do it uniformly across the whole universe. If you say that God created the light instantaneously on the way here at a point where it would arrive at the moment of creation 6000 years ago that is an arbitrary claim. There is no reason to even consider it.
If you see a car going 50 miles an hour, do you assume it has always traveled at that speed?