Try this:
With the computer on, just close the laptop (don't do anything in Windows, just close it). Wait a couple of minutes, and open it up again.
If the laptop is now off (i.e. you need to press the power button to get it back on), then closing the lid puts it into "hibernating" mode. In this case, I would wait for the laptop to shut down before closing the lid in future.
If the laptop is still on (i.e. if screen is off, it comes back on if you move the mouse, with no messages about Resuming Windows or startup sequence etc.), then closing the lid has no effect. In this case, closing the lid while shutting down won't cause any problems.