Lilfoot has it right. 140-144 would work just fine.
Being a newer rider I wouldn't recommend a v-rockered type board (Lib, arbor, burton v-rocker, etc.)... Stick with camber or a camber hybrid. Also, if you're not aware of the subtleties of binding setup, take it to a shop to get it set up.
Lastly, if you have any numbness while riding, do not assume it's normal. Numbness is bad and you should be able to snowboard pain free. If you feel pain/discomfort when you ride, go to a shop and get your boot fitted properly. They will recommend insoles, heat mold the boot, and sometimes add inserts to relieve pressure in certain areas.