So your guess is what, that this T-Rex was alive 10-12 thousand years ago ?
If you are taking the creationist side, then we have no possible yardstick to measure 60 million years - nothing whatsover has existed that long. And everything that IS fossilized occured with in that time span also, so it does not take that long.
If you are taking the evolutionist side, then T-Rexs existed basically unchanged for 60 million years untill just recently.
I'm not exactly a young-earth creationist. What I believe to be the case is that once you admit the possibility of even one cosmic catastrophe such as the flood at the time of Noah, then basically all of the assumptions which dating schemes are based on go out the window. Bob Bass once redid Lord Kelvin's heat equations for the Earth with a maximal figure for radioactive elements included in the calculation, and came up with a maximal age of about 200 million years for the planet. I have a hard time seeing how you could square that with dinosaurs being around 60 million years ago.