id just tell her that it doesnt change you... and has she done it before...? if not id ask her how does she know it changes you?

if it comes down to it... its only pot right? if you really like her fuck pot! u just gotta decide whats more important.

actually ive had a similar experience.. when ive been with a girl that was really against pot. from the begining i was upfront about it. i told her that i smoke it ocassionally (every 2nd week or so and that i used to do it regularly) which is true... she didnt like it much but but she liked me enough that she could deal with it... however if i smoked up regularly i dont think she ever wudda put up with it.