This is a loaded question and it totally depends on what definition of regret you assume.
One way to define this word is a feeling of remorse for having done something of your own fault that caused pain to you or others. Another way to define it is more of a feeling of loss. Now the first form of regret is something that as Christians, we should never have… but the second form of regret is certainly plausible or even common.
There was a line in the movie “13 going on 30” where the daughter is asking her mom if she had any regrets. In this moment, the mom was looking at the first definition and said no. The daughter of course was shocked and said… ‘haven’t you made any mistakes’. The mother said ‘of course I have, but it was those mistakes that eventually led me to be who I am, and I would change that’. You see, she had sorrow and loss even (the second form of regret) but didn’t look at the mistakes in her life with regret (the first form).
This makes me think of how I regret not finishing my dream to become an Air Force pilot. I hit a road block in college but instead of working around that road block and still making that dream come true, I turned another direction. While I do have regret (a sense of loss) for not pursuing that dream, I don’t have regret (a sense of remorse) since my life since that decision had brought me to this point. My decision to follow Christ, my marriage, my four kids… all came AFTER that change in my path. I am exactly where God wanted me to be, so therefor I have no regret in the first sense.
God is this way. Being perfect and not bound by time, he can’t actually ‘make a mistake’. It would be impossible for God to have the first form of regret. However human history is filled with God having regret in the second form.
1 Samuel 15 has an excellent example of this seeming conflict. First Samuel says of God, “And also the Glory of Israel will not lie or have regret, for he is not a man, that he should have regret” (v29). Yet he ends the chapter with “And the Lord regretted that he had made Saul king over Israel.” (v35)
Many have looked at these two verses (only 16 lines apart) and wondered how is it possible that God cannot have regret, yet still had regret for making Saul the king of Israel. God actually knew this moment before he appointed Saul as king. He knew Saul would fail. In fact, this failure was crucial to the long term plan God had, requiring Christ to restore us to Him, instead of an earthly king.
Don’t regret (in the first sense) the decisions in life that have changed your path, even when your path seems different than you planned. Instead, turn to Him. Seek wisdom on what He would have you do with this path you are on.