Why did I get in trouble when my friend shoplifted and I had no idea?

Me and my friend were hanging out and then he decided that we should go on a bike ride. So I decided to go with him. We rode down to a corner store, (which isn't far) and then kinda rode around from there. he was getting really thirsty, and we had no money on us, and so he thought that we could look around for a bag, and some bottles, and get some money off that. well we couldn't find anything, so I decided to go into the store and loom at the price of water. (little did we know, we could get some glasses of water for free) so we were just about to walk out of the store and then he talked about shoplifting some gum. I was telling him NO! NO! NO! but of course, when we walked out, and got to our bikes, he took out some gum. less than 10 seconds later, the store owner came out and I was holding it because i was going to bring it back in. I freaked out in my head and my heart was pounding! so, to make this part of the story short, she called 911 and the state trooper came, got our info, called my parents, and got a good talk to. he then got me to tell my side of the story, and i did. but there was that suspicious part on which i was checking the price of WATER! really? course it sounds a little dumb but really? now my friend and I cant go into that store what so ever!