Here is the fatal flaw of your logic...<quoted text>
The earth has been MEASURED, using MULTIPLE methods, to be slightly over 4.5 billion years old. That is NOT a theory or hypothesis. That is a MEASUREMENT that is CONSISTANT across multiple means of discerning the age of our world.
You ASSUME knowledge as to HOW the earth was created.
If you're and atheist, you assume that it resulted from extreme heat 4.5 billion years ago.
If you believe that an intelligent being created the earth, you assume that he created matter out of nothing, or that the matter of the earth was in a state of extreme heat at the time of creation.
You cannot assume that the state of matter as indicated by concentrations of radioisotopes parallels the time of creation.
If random forces created the earth, the matter of the earth might come together one million years ago through coalescence of 4.5 billion year old rocks.
If God created the earth 10,000 years ago, He might have used 4.5 billion year old rocks to do so.
There is no scientific way to determine when the matter of the earth came together to form a sphere. Matter is, as far as is known, infinitely old.