At the low-end pricepoint snowboards tend handle very similar to each other(from my experience). The only difference I see is newer boards tend to be rocker, while boards from a few years back are usually still traditional camber. I learned to snowboard on a traditional cambered board so I can't say how much easier a board with rocker is to learn on, though I always hear it's much more forgiving when you're figuring out how your edges behave on snow. If you're unsure if the board is rocker or camber have one of the store clerks lay the board on a flat surface. If it arcs up at the tips it's a rocker board; if it arcs down to the tips it's regular camber.
Anyways, ss long as you get a board in your weight range you shouldn't have any problems learning with it; in your case a 160 sounds about right. And yes you'll most likely want a wide board at a size 12.
Cheap out on the board and bindings, but don't on your boots. Comfortable boots can make/break an enjoyable experience while snowboarding.
Good luck learning but don't count on not becoming addicted to snowboarding. It's a drug. Once you get a real taste you'll come back for more.