A lot of it, is where you are riding.
If you never see powder or very rarely, you could get an even shorter one.
If you live in B.C. or the PNW, you'll drown on those itty bitty boards, we get thick wet heavy snow most of the time.
I'd stick to the 162, you won't notice the difference on hard pack days but I bet you will on pow days.
++Bigger boards go faster, ride smoother & are more stable.
If whatever doesn't kill you, only makes you stronger.
Then I am so close to immortality