Yo Bingo - welcome to Epic!
There are a lot of factors that can influence what length board is optimal for a rider. Some of these are trade offs.
Float - the longer and wider a board is, the more float it will have in powder. If you're not riding a lot of powder, this is not a big concern.
Flex - in general a longer board will be easier to flex than a shorter board of the same construction
and the faster you ride, the easier it will be to flex the board
and the more you weigh, the easier it will be to flex the board
and the stronger you are, the easier it will be to flex the board
and the narrower your stance width, the easier it will be to flex the board
If a board is too stiff, it will be harder to turn. If a board is not stiff enough it will wash out of turns.
Rotation - the longer a board is, the slower it will be for doing rotary tricks like 180's and 360's.
Steering - riders tend to find shorter board easier to steer/longer boards harder to steer. This is more important for beginners. As one gets more experienced, one's "tolerance" for length increases.
Speed - longer boards of the same construction are faster than shorter boards
I'm 5' 10" 240 lbs and ride a 168 Burton Custom Wide. It's long for my height and a very stiff board, but not for my weight/strength. Still, I've been encouraged to go shorter and more flexible.
The best way to know what length is right for you is to take advantage of demo days and ride as many different boards as you can and vary lengths of the same board. Even then it is hard to account for all the other differences between boards.
All that said, I'm guessing a 162 is as long as you'd want to go. Unless you're riding a lot of powder or mainly making big honking long radius high speed turns, you could go shorter. It's hard to get a board that is too long and grow into it. It's better to get a board that's on the short side and deal with growing out of it until it's time for the next board.
