"Don't have kids because you will regret it. Don't marry her, don't leave him, don't take that job, don't move cities because you will regret it." It is quite common for a close friend or family member to tell you that you will regret a big decision, but according to the philosopher Derek Parfit, they are always wrong to do so.
Parfit gives two reasons for this. The first is that the person who you are now has their own reasons for acting. You are a certain brain with a certain environment, working on the best information available to you right now. The second is that the person in the future who may or may not come to regret that decision is actually a different person. They will have different values, and they will see the world from a different position, so even if they do regret it, in a sense, they are different.
Parfit's theory of regret is tied into his wider theory of psychological continuity, where he argues that there is no one static ego, but rather a shifting self that changes depending on your current psychological state. And so, your past self acted on the reasons and the psychological states that were valid to them at the time.
So yes, you may now have to deal with the consequences of a past decision that your past self once made, but to carry the emotional burden of regret is, according to Parfit, irrational. The person who made that decision was operating in a certain world, and with certain information available to them. You are doing your best, and who you once were was doing their best as well.