There are basically two reasons you should keep that novel to yourself for the next few months. Listen to Kelsey. She has learned pretty much everything the hard way and she wants to help you. She is now done with the annoying third person narrative. Wait, now I'm done. Okay. Onward.
1. It isn't ready.
It doesn't matter if you write really clean first drafts (if there is such a thing). It doesn't matter if you feel really good about it. Your novel is not ready for agent eyes. I don't want to metaphorically slap you across the face or step on your dreams. Honestly, I speak from experience. With my first couple of books, I was so excited that I didn't do near enough revising. And when the rejections came pouring in, I realized I could have saved myself the effort and heartache - not to mention the agent's time - if I had just done the work.
2. This is a busy time.
There are going to be tons and tons of people who don't wait. They're just not as smart as you. So around the beginning of December agents will see an influx of queries in their inbox. The wait will be longer. More eating of chocolate and biting of nails. Enough said. Right?
Get editing, you wonderful writers! I believe in you.