No one knows what light is nor that it always travels the same speed throughout all time, space and matter. The creation was finished or mature when God made it. Adam was full grown, the trees had fruit on them, the star light was visible, etc. Let me elaborate on these 3 points. First, no one can measure star distance accurately.
Man measures star distances using parallax trigonometry.
By choosing two measurable observation points and making an imaginary triangle to a third point, and using simple trigonometry, man calculates the distance to the third point. The most distant observation points available are the positions of the earth in solar orbit six months apart, say June and December. This would be a base for our imaginary triangle of 186,000,000 miles or 16 light minutes. There are 525,948 minutes in a year. In simpler terms, a triangle like this would be the same angle two surveyors would see if they were standing sixteen inches apart and focusing on a third point 8.24 miles away.