Son ain’t been shining for 15 billion years (that’s milliards for you who know what one is). Son is 4.57 billion years old.
Big Bang is currently reckoned to have happened 13.7 billion years ago, and was mostly a dark place with no stars for the next 400 million years.
That cuts your photon problem by at least 70%
Link to question below, question is way down at the bottom.