When I was younger, I wished I could have done my life over again, only with the knowledge and wisdom I have now. But, there is no possible way to go back and even if I could, how could I or would I change anything that's already happened?
Our history, as well as the earth's is already written and cannot be changed. All we can do is learn from past mistakes and not make them again. And, who's to say what was a mistake? At the time such events were happening there were probably those who didn't think it was! Maybe we're doing things right now that our descendents are going to criticize hundreds of years in the future!
If we have the power to recognize that something we're doing is harmful to us or our planet, and alter our course to stop or prevent it then we are progressing. If not, we sincerely hope that what we're doing won't do irreversible damage that future generations are going to have to deal with!