Do it! Although the 'stated' goal of Nano is to write 50,000 words, it's more about having fun and being part of this world-wide anxiety attack!

I do Nano every year, though I've never won. Partly because I don't take it too seriously and just use it as a writing excercise and partly because I meet with my Nano group and we end up chatting or doing other fun things.

All this to say, DO IT! No one ever looks down on someone for not completing it or even cheating a bit to finish on time.