Should i get a 146cm or 144cm snowboard?

i'm looking to get the 2010 forum spinster snowboard and i'm not sure what size i should get. i'm 5'5" and 115 lbs. im currently riding a 150 forum manual and i''m looking to get a smaller board for doing more park stuff. i have a guys size 9 boot right now and don't know if the 144 will be wide enough.