you dont need to shut it down tho, just shut the lid, it will sleep, then when you open it its all there ready and waiting for you.
this is assuming your not shutting it down cos your storing it for a week etc, but for general day to day just shut the lid
it will only stay awake if you have external keyboard/mouse/monitor plugged in
hope your enjoying your first mac, my new 2.4 ali is only my 2nd mac,
as the saying goes " once you've had mac you never go back" or something like that!😀