Some people find that task so difficult that they make no decisions at all. We all need wisdom and understanding in order to make wise choices, but we are limited in so many ways from knowing everything that would help us make the absolute best decision. Absolute certainty is a moment that never arrives. We can lay the best plans and unseen events can arise and change everything. Jesus told of a man who laid wonderful plans for things in this life, but was not rich toward God. His soul was required of him that night (Luke 12:16-21). There is great truth in that parable.
So what to do? Why, go ahead and gather all the information you can. Weigh the pros and cons and then make your decision. Make it as wisely as possible because absolute certainty does not exist for us in the flesh. It is in using our minds wisely and then adjusting when we need to within our plans that we grow into the character that pleases God. Never fear failure, but be ready to get up and try again. That is how we learn and develop character.