Since you are leaving at 3AM, I hope you bought a headlamp at REI. You may be too excited to sleep much the night before. Your permit allows you to leave at midnight. That gives you a better chance of getting back before sunset.
High mountains make their own weather. You need to carry a wind proof, water proof outer layer. Also, one warmer piece as well.
Take some aspirin (not Aleve or Advil) before starting as a preventative for altitude sickness.
Drink water on a schedule. If you wait until you are thirsty, you are already dehydrated. Add some sport drink powder as well.
You may not have much appetite. Take high carb foods and snacks that you like and will eat. The trail burns a ton of calories.
Whitney isn't going anywhere. If you start feeling the altitude or the distance, turn around and go back. Every step of the hike is beautiful. Your trip will not be wasted. If you are tempted to push for the summit, remember that it is only half way. It's still 11 miles back to your car.
Please report back on how you did. Good luck!
