One of the things that comes with growing older is being able to look back and say to yourself, "I can't believe I really did that; what was I thinking?" Hopefully we can look back at those experiences with a smile. You can't go through life thinking about what could/might have happen(ed). Another way of putting it is to make the decision and work at making it the right decision.
This is a world of infinite possibilities and moments. Enjoy them!