We actually do have the one planet (Venus) in our system which actually is ballpark for some sort of a 6000 - 20000 year age like you'd get from Bible chronologies and Venus LOOKS like that: 900 F surface temperatures, major thermal imbalance, major upwards ir flux, 90-bar CO2 atmosphere, statistically random cratering etc. etc. etc. Since Earth and Mars do not look like that in any way, shape, or fashion, you have to assume that they are much older than that, but not billions of years old.
Bob Bass, one of America's best mathematicians over the last century, once redid Lord Kelvin's heat equations for the Earth WITH a maximal possible figure for radioactive elements, and came up with an upper bound of about 200M years which I would take as an absolute upper bound. If I had to put money on such a guess I'd say more like a few hundred thousand to a few million years.
That is of course, viewing our planet as a pile of rocks. Our living world in its present conformation is likely more like five or ten thousand years old as per the Bible. For that matter there are easily recognizable pictures of known dinosaur types in Amerind petroglyphs and other art work and descriptions of dinosaurs both in Midrashim and in Amerind oral traditions so that you assume there were leftover dinosaurs walking around at a time just prior to the flood, but I would assume the real age of dinosaurs would be more like a few tens of thousands of years back.
I'll grant it's possible for a given sample to have formed with all the necessary daughter elements in the mix to give a false representation of age, but it's irrational to believe that they all did.
If the Earth is, at most, a few million years old, then we shouldn't be finding Uranium ore with more than a few million years worth of accumulation of the daughter elements, but we consistently find it with accumulations indicating a much longer period of decay.
What exactly is that? Is that a biological, tectonic, or some other taxonomy?
Mammoths, Mastodons, Sabre Tooth Tigers, Great Deer and Elk are not dinosaurs, they are mammals which died out about 10,000 years ago due to the retreat of the glaciers after the last ice age. they are the ones you see in petroglyphs and cave walls.
The last of these to die out was a population of small mammoths that died out in about 3500 BC on an island in the Arctic.