In retrospect there's much you could have done differently. Things would be so much different today if you had only known what you now know. Life would be easier; you'd weigh less; you'd have more money. The list goes on…
Cut yourself some slack.
You made the best decision you could with the information we had at the time.
The key is to remember that and then act on the information you have.
At any point you can decide to change things and then make that change happen.