My whole life theory is to not regret anything because everything you did has made you the person you are today. No matter what you do you can't change the past, so suck it up and move on. When you look back on even some of the mistakes you made, you can't help but laugh when you see where those mistakes led you.
This goes in line with the whole idea that your life is mapped out for you, the good, the bad, ect.
Good Luck with your Essay!