I'm not a teacher, but I'm a strategic over-planner. My best advice: take everything you have in mind and chuck it out the window.
Figuratively.
You're right, you have no idea, and from here til whenever you have no idea. Short of preparing for an earthquake, there's not much you can do. When I get nervous I 'spaghetti sling'- I try to come up with all sorts of little things and plan for all sorts of tiny eventualities. In the end, it comes down to this: What are you 3 largest, most likely scenarios. Plan for those 3 things. Be done with it. Launch at 80%- you'll never be perfect and you'll drive yourself spare trying to cover everything. Good enough is ok. Meditate, take a walk, do something completely non-related that will require all your concentration. It'll help keep you from losing it.