The pilot reported that while landing from his sixth Experimental Aircraft Association Young Eagles flight for the day, the airplane encountered a downdraft and variable wind conditions causing it to bounce several times. The pilot attempted to maintain control, but the airplane veered to the left off the runway and impacted the terrain in a nose low attitude. The airplane subsequently nosed over and came to rest inverted. The airplane sustained substantial damage to the vertical stabilizer and rudder. The pilot reported that there were no preaccident mechanical failures or malfunctions with the airplane that would have precluded normal operation. The pilot reported that prior to this flight, hazardous weather was in the area; however, the weather appeared to not be a factor in the area, and he thought he could complete the flight.