vdbfamily, I'm tempted to say that only young earth creationists are true believers. The rest have abandoned the bits as they were proved wrong, which is not the act of a true believer.
It's possible to claim that god created the earth millions of years ago and set evolution in motion and the majority of Christians seem to go that way now. But god said he didn't do that. In fact the whole point of the crucifixion is lost if Adam & Eve were fictional.
Still the reason most Christians have abandoned a young earth is that they see that it's not compatible with what we already know.
You notice that even that woman scientist who was examining the soft tissue was a Christian. You might wonder why she'd be deliberately deceiving other Christians.
I'm not scientist enough to lay out all the evidence for an older earth, but there is a lot of it. We know for example how far away many distant stars are. When you look at a picture from a telescope of a star 60,000 light years away you are looking at light that started out 60,000 years ago.
Young Earthers try to find ways to work around that, but not successfully. Some have said that light used to go faster, but then god slowed it down just before we learned how to measure the speed.
Others have said that when god created the stars he also created the light that was already nearly here so it would look like it fitted. They are probably the same ones who say god buried fake dinosaur bones.
The second creation thing could work too, but it would be hard to make it fit in with the other things that god has done and said. After all we're taught that god made the world to put man on it. Making a dinosaur world first would be pointless wouldn't it. So would creating a whole universe and waiting billions of years just so it would look old to us and encourage disbelief.
Evolution is mostly accepted by Christians because it can be shown to be happening now. Also consider why god would create people with mistakes like the appendix. Not to mention making the heads of babies too big to be born without difficulties. The Perfect Design people miss the fact that we are far from perfectly designed.