<human>: Can you summarize the given text in a few sentences?

So my parents recently discovered that I had consumed a pot brownie. Now this is the second time I've been caught with pot by them, but I was 16 before and I am 18 now. I'm off to college in a couple of months and am generally granted lots of independence. They are angry because they feel that I've betrayed their trust again by doing this when I said I wouldn't. In their minds, marijuana is very bad for your health and leads to failure. I simply want a way to discuss the issue with them and assert my independence to decide what I do with myself while still acknowledging that I live in their home and they pay for my schooling. Any ideas, articles, or approaches that anyone has to offer? Any help would be greatly appreciated.
<bot>: I need to discuss marijuana in an adult way with my parents who believe it is detrimental to health, mind, and education.