This has been addressed continuously since Darwin, and your opinion is simply your opinion against all the rest of biology.
Most of Darwin's data on natural variation was derived from interviewing animal breeders about "sports" or mutations (yes, breeders know the difference between a new allele and a recessive trait).
Darwin used this data to calculate the natural rate of variation. He then used this rate to calculate the time necessary to evolve from a single cell to the multi-celled creatures we see today.
He arrived at a minimum age of the earth of several hundred million years -- about thirty times the maximum age calculated by physicists of the time. One could say that Biology produced a better estimate of the age of the earth than physics, at least until the discovery of radioactivity.
So, Darwin estimated the age of earth at a couple hundred million years.
You reckon we should keep using that number?