i would probably start off with firearm safety as many have mentioned but in all honesty would probably get into waterfowl or upland game birds as my first quarry.
the fundamentals gained duck and pheasant hunting can be applied to big game hunting and there are generally more opportunities for success than starting off deer hunting.
i personally would be apprehensive taking the rookie hunters i know out with me as it takes time to develop the familiarity, skills and ethics to make it a safe hunt for everyone.