First, no creationist believes the earth is 12,000 years old. I don't know why you made that up, but you did.
Second, your 'conversation' is actually about ancient Greek mysticism: they're the ones who believed the 'Gods' put fossils there to fool/test us. Christians don't believe that.
Third, dinosaurs in the bible: Behemoth.

I've met three types of people who call themselves atheist:
- read the bible, liked rules against murder and robbery, liked Christ, saw what they did to him, no thanks. Tend to be educated enough to know things like there are 14.000 surviving ancient documents acknowledging the existence of Christ, more or less, tend to have seen hypocrisy or heard doctrine in real life that seem as if nothing's changed since now and then;
- spent a lot of time in the great outdoors, farmers, soldiers, hunters and so on. Noticed that nature cannot be random as it's too well organised. Realised something has to be out there. Attended church, could not believe what they heard, not going back, and;
- the third group use the term 'atheist' to cover for something else. I think that's you.