The day before the long run...

Less than 24 hours to go before my attempt to complete my first long training run in many years. I am actually kind of nervous. I am afraid of not being able to complete the run and being extremely depressed about it. I'll try to go through my old pre-long run day routine which involves making sure I am well hydrated prior to the run and to have a substantial carb rich meal the night before. The plan for the actual run is to get up at 4:45 AM and be out of the apartment by 5:00 AM. Depending on how I feel after the first couple of miles I'll decide whether I will attempt to do 12 miles or stick to the original plan and only do 10 miles. I think the toughest challenge is to figure out what pace I should keep to be able to complete the distance.