All the background information conducted by US Army, Navy, Coast Guard, Air Force are confidential. They don't share any information with another department. If you don't have felony or convicted in marijuana related crime you and your parents will be fine. Someone told on you cannot be charged as felony, only with the proper physical and chemical evidence you can be charged for felony.
On the other hand, US Army can reject you (if you are non citizen) for any reason, and you already gave them the ground of suspicion.
Best of Luck