Am I an adult for this?

I’m in the 9th grade. Mom and I sat and sorted out the issue of homework. When we began to argue with her in high colors, how to make it correctly. I was sure of my innocence and I told her: “Oh, mom, shut up.” She was very offended by me. She said that for such words she would give me lips next time. As a result, her method also turned out to be true, but I still think that in our time you can talk like that. In the end, we are already a completely different generation. And always one generation differs from another. But still I want to listen to other people what you think about this?