A man rarely has all of the guidance that he needs to make a decision beforehand, but a wise man still decides without worry.
Earlier in my life, decisions were really troubling for me because I don't have all the information that I would like to have before making them. "How will it turn out if I go this way?" and "What will I feel like if that does not work out?" are the kind of things I would ask myself. Of course I can't know these things, so I must make a decision without knowing these answers.
In a graduation address at Stanford, Steve Jobs (Apple computer founder) said "You can't connect the dots looking forward; you can only connect them looking backwards. So you have to trust that the dots will somehow connect in your future. You have to trust in something: your gut, destiny, life, karma, whatever." He is right that you do have to pursue a path and trust in something. As Christians, we have something to trust in that is far more trustworthy than the things he mentioned. We can trust that the Creator of the Universe is going to use our lives for His Glory. So should we not be totally confident in our decisions? That is one thing that I have seen clearly in my life. Even when I have not known what decision to make, or even made the wrong decision, I have been put in the place where I need to be, so now I don't worry (as much) about those things.