I'm not sure if I would go back and change anything or not. Certainly, there are things I regret, but I'm not sure how changing them would affect the overall trajectory of my life. Actions can have unexpected consequences, and I wouldn't want to create new problems in my efforts to change the past.
Overall, I guess I'm currently happy with how my life is going. Sure, I'm worried about how a lot of things will work out, but for now, I would rather just wait and see how they go. I think I'd rather go through most of my life, see what things I regret in the long run/if there are any elements that I really want to change, and then go back and start again. It's just too hard to say how the things I regret now will affect me in the long term, and I wouldn't want to erase a potentially valuable experience.