Yes you do, at least until January 2018 when the law is intended to be implemented, although there are others in the industry that claim it might take even longer.
Yes, the law applies now, but if you do not have a card then you cannot legally purchase marijuana. Dispensaries will not open until 2018. You are only allowed to go into a dispensary NOW if you have a medical MJ card. You can possess less than one ounce of marijuana or edibles if you were GIFTED then unless you have a medical MJ card. So might as well get one.