I was the same way at my first meet. Lol.
1. Since it's going to be cold, KEEP WARM. You do NOT need your muscles to be cold and tense for your events.
2. Eat things with potassium! Peanut butter and bananas are GREAT during track meets. Before the meet don't eat a huge greasy breakfast. I learned this the hard way.
3. Don't be uptight, just relax. My first track meet, our coach started playing baseball with a rolled up newspaper and bees that were flying around, he did it to keep the mood light. So bring music, run around and be a goofball, it helps a bunch.
4. Be sure to get a good nights sleep! You don't want to be AWOL in the middle of a race. I even splashed some ice water on my face before I walked out the door.
I hope that helps. :3