The days of our years are threescore years and ten; and if by reason of strength they be fourscore years, yet is their strength labour and sorrow; for it is soon cut off, and we fly away.
So what do we do? Anything. Something. So long as we just don't sit there. If we screw it up, start over. Try something else. If we wait until we've satisfied all the uncertainties, it may be too late.
When I have a problem I pray about it, and what comes to mind and stays there I assume to be my answer. And this has been right so often that I know it is God's answer.