If you were there in Eden a day after it was all done, and saw a rock, would you think it was billions of years old? The isotope ratios would be there. The thing is, the reason for their existing would not have been radioactive decay. That only could start after the rock was there. Putting aside the one day of radioactive decay because it would be too tiny to be significant, all the ratios would be there because that was how it was created.
Natural processes can only start after creation. Science has used only what we can observe in the rock, such as the radioactive decay rates etc to come up with a model of how old the rock was and how it came to exist.
Scientists examining that rock, in Eden, if they were transported there, would declare the rock to be billions of years old.
Do you agree?