All I can say is that its a good thing that shes found out - it had to happen sooner or later. Let her meet your stoner mates a few times, so she knows they are decent people and not chavs etc. Unless of course they are a dodgy bunch...

Anyway, youre already on the right path to convincing her that herb isnt all that bad. Youve told her about your grades, and for most parents thats the number 1 worry - that their pothead kid is going to become a bum for the rest of their lives.
If I were you, I would sit down with your parents and have a really good discussion about how weed ISNT affecting your grades, ISNT making you lazy, and ISNT getting you involved in crime.

All the best mate :thumbsup: