It doesn't disprove a young earth since the age of the universe has nothing to do with the age of the earth. It does however disprove a young universe. At least, it does without invoking some crazy, completely unevidenced stuff like "God created the light en-route to earth!".
But in the bible it says "In the beginning God created the heavens and the earth" Gen 1:1, and he said "Let there be light" Gen 1:2 after creating the earth so earth should appear to be OLDER then we could see the oldest light to be. But then it goes on to say that he created stars "to divide the day from the night" and "to give light upon the earth" on the third DAY so now I'm getting lost. This is just in Gen 1:1-19 in the King James, so I gues if the bible is that confusing trying to add science would muddle it up even more.
And sorry for taking so long to reply.