You are correct that rider height has nothing to do with board sizing. This particular board however is on the soft side and in 152 cm should be easily pressable with your 140 lbs. Are you comfortable with your stance? Is it ultra wide?
i'm 15/15 at a wider stance. i'm pretty comfortable. little wider than shoulder lenght. i can do 360's on flat grounds with minimal pop. makes it that much harder vs if i had more air time to spin.
i'll have to take a video and upload for you guys to see...
2010 152 LibTech Skate Banana, 2010 Ride nRc Bindings