One thing that I can't quite wrap my head around is how light is traveling to Earth from 14 billion light years away, aka the beginning of the universe.
The way I see it, the universe itself was very small 14 billion years ago and has been steadily accelerating in size since. So the photons that left a star that existed 14 billion years ago couldn't travel for 14 billion years because the universe itself was probably only a few million light years total in diameter. The universe is not expanding faster than the speed of light, so that photon should have hit the end of the universe before now.
What piece of this puzzle am I missing?