Dropped charge, will this stop me from the Marines of Air Force?

heres a long story short. in 9th grade got caught with poss of marijuana i only smoked in once and got caught lol go fiigure. but anyways i wasnt arrested on the spot like 6 months later i was called for fingerprints. THE VERY NEXT DAY i was called by the juvinille punishment guy and he said the charges were being dropped and the prints being destroyed. will this stop me from getting into the marines (infantry) or the airforce (contractor). should i admit to smoking once or the charge. please somebody who knows give a good answer =) thanks all