It's so interesting that you mention this...My best friend and I (who were complete heathens growing up lol and are now Christians) were having a talk about the age of the earth last night.

He was on the fence, didn't agree with new earth or old earth but was open to learning more.

I am a new earth believer, and while I don't claim to have all the answer, I do have to take the bible for what it says. Here's a fantastic feature length movie that came out a few years ago, about the age of the earth.

It's absolutely mind blowing.