Take it as a learning experience.
Weed does not equal a drug.
Until your parents are more accepting to the fact that you choose what to do with your body, don't smoke weed in their house/keep it in their house unless you have an amazing hiding place.
You'll probably only be grounded for a month.
Get a new hobby (guitar/piano/musical instruments/writing/skating/poetry,etc.)!
This is all I have to say.