I don't think a child should be introduced to pot by their parents at all. I think the parents should be really strict about it so the kids will want to be secretive about it. I didn't start smoking until I had already gotten a good job at 16 and had it for a year. And even then it was something that I slowly became more comfortable doing. Now I smoke in my room every now and then, but my parents don't (openly) know about it. They might know, but it's not something we talk about, and I think that's the way it should be.