Like it or not, your parents are right about a lot of things. They have probably been there too. Plus you are living in their house, show a bit of respect and just consider what they are saying. Looking back at when I was in high school I had a lot of issues with my parents and I got caught with shit a couple times. They weren't easy on me but now that I've moved out they won't get mad about my smoking, they know that I can make my own decisions. Plus smoking when you aren't at home is nothing like when you where there. You don't have any worries which makes your high that much better.

I'm not going to tell you to do anything, but I would listen to what my parents were saying and have some self-reflection time.