^ Exactly.

The number one thing to do, at least in my many experiences, is to show them that you can still be intelligent. If you start coming home blazed as fuck asking, "Whaaaaats ferrrrrr diiiiiiinerrrrrrrrr?" then you deserve to get your ass kicked.

Also, bring up the fact that it's virtually impossible for a human to overdose on weed.

And, I know it's kinda Brady Bunch-ish, but at least she gives a shit about you. In her mind you're doing bad things to yourself and she doesn't want it so. Just keep explaining, calmly, that it's a gift from nature (I compared it to a sunset) and only people who are fuckups originally let it take their life over.