What size of snow board do i need?

it depends how big you are

12 inches long.

Don't just pick a board between your nose and chin that's a rookie mistake You need to take into account a few things your height,weight,riding conditions,riding style"all mountain,freeride,freestyle",foot size and skill lvl Once you get those nailed down you can narrow down your board genre and size, Generally people go largest on freeride boards for stable carving and float in pow, Mid range for an all mountain board and smallest for those park rats. I'm assuming size 12 shoe is your snowboarding boot size? generally people go 1 size down on snowboarding boots than there regular shoe size, If that is the case than you'll want a WIDE board or you will deal with possible toe drag. If you are just looking to go down groomers nuthing fancy than I would look in the 158-160 range for a nice solid carving board. Something to remember is the longer the board the more stable it will be for you on high speed carves, The shorter it is the easier it'll be to spin around butter and just dork around on runs. You can find some good sales on boarder specific gear at these websites. http://backcountryoutlet.com http://moosejaw.com http://dogfunk.com http://seirrasnowboard.com http://the-house.com http://www.boardparadise.com/snow/ http://www.whiskeymilitia.com/ - timed sales, you could get lucky though.

Correct me if I'm wrong, but I believe you want one that goes up to your chin?

well, snowboards should be up to at least your nose, but it can be up to your hairline/forehead, if you don't have hair. Also, if you are more in the park and going off jumps, the board should tend to be shorter, for tricks and spins! glad to help!

1) you need to explain more 2) you will need atleast a 7 ft. long snowboardif your 12- 20.

About the height of you face