I'd suggest that you tell them the good effects. first, ask them if they would prefer u smokin cigs, which are way more nocive, and weed isnt addictive.

second, inform them about the good sides of weed, and that u like it, and why wouldnt u smoke it if it brings u good things.

and just tell them they cant force you to not smoke anyway, and that if they dont want u to smoke inside the house its kool.

well after few weeks theyll get used to it, and it may become cooler btw them and u