I can't help thinking that it must be hard being the younger member of a family. Your parents are accustomed to teaching you, so it's difficult for them to accept that you know things they don't. As others have said, example is the best teacher.
For me, as the mother of grown daughters, it's interesting to see the different reactions they've had to the PB. My oldest daughter has wholeheartedly embraced the primal way of life. My youngest daughter agrees with the organic, local aspects, but hasn't taken the time to understand much of the philosophy. But, my middle daughter, who recently moved back home for a short while after living in Italy, complains that there's too much meat, and can't embrace eating saturated fat, but then recognizes she feels worse after eating pasta.
It's a journey, that's for sure, and they've all watched me go through "diet phases" over the years. It will take a while to demonstrate that the PB is much more to me than a phase. As my daughters see the changes I believe they'll be inspired to more seriously investigate.