[NC] Will I have my offer rescending for omiting a few experiences from my background check?

Hello, I'm a current college student who is filling out a background check for a summer internship. I have work experience in landscaping but I don't have any W2s or anything to prove it. I also didn't have a supervisor so there's not really any way to prove my expereince. Is it going to mess up my offer if I leave out something like this? Also I will need to likely omit an experience about a high school club, since I never had the phone number of my supervisor and she moved schools so I have no way of contacting her. 2 experiences feels like a lot to leave out, given I only had 6 total, is that enough to screw me over or will that be ok?