I brewed my first batch Wednesday, so congratulations to you, too.
I had my fermentor in a kitchen cabinet. I was worried about it being too cold as well since at night the house got down to around 60, though it would warm up during the day. I was worried and posted here as well
Long story short, I ended up moving my fermenter to on top of the refrigerator, where its still not in major traffic areas and tends to stay warmer and more regulated.