"I used to be a young-earth creationist until I got into astronomy. "
My reply:
This statement implies that astronomy conflicts with "young-earth creationism". Please look up Dr. Jason Lisle, whom I have pointed to previously for different reasons, as his Ph.D. from an Ivy League school is in astrophysics.
Here is a good place to start:
Dr. Jason Lisle | Answers Outreach
The issue of seeing "distant starlight" is one he seems to specialize in. The biggest point he makes there is that even for the 4.6 billion year old Earth theory, there hasn't been enough time for light from the most distant stars we see to reach our Earth, and yet we see them. Thus, both sides of the debate have this same problem.