You must understand that Light Years is term used to make you feel insignificant. Light doesn't live on forever and ever. It fades. If light lived on forever then you'd never have night time as light from the universe would constantly be shining in your face.
The Universe is 13.7 billion years old and yet we can “see” objects that are now more than 45 billion light years away. Let that twist up your brain when you go off to sleep tonight.