I am getting my first board this for this season but I don't know what size or anything. I want a board that is decent in the terrain park but mainly I'll be searching for powder, so basically i guess an all mountain board? and is a used ok? I am 16, just at six ft. and roughly 150 lbs. any help is appreciated, thanks. o and i've gone snowboarding a few times before, i just always rented, so i'm not a complete beginner if that means anything