What size snowboard should I get?

TO BIG! Your height has little to do with it really, you should go with about a 154 for park. Your style of riding would be nice to know but i'm uming you want to do park with a little mountain. A 154-155 would work for that, just don't get an over sized board that's the worst you can do. I've been riding long enough to know he height of a board, if its only those 2 though go with the 156 if you have to. i still suggest a 154