California Airsofting Problem..?

I was shooting my airsoft guns in me small backyard which is closed off with a brick wall about 7 feet high. I was shooting at soda cans and we have a really stupid neighbor who called the cops. The cops came and said that he claimed a bb fell in his yard. And then they said it is ILLEGAL to shoot an airsoft gun anywhere in Irvine California, even on private property. It's considered misdemener. I think that's bs, and i was wondering can i shoot inside my house? Lol, or in my backyard anymore?What's the worst the cops will do? Thank you.