As for telling them my devotion to Dharma, I think it would be wise to tell them that once I myself am sure of my devotion.
Namaste TheOne,

I think that might be the wisest thing to do. Unless you have been seriously following the Hindu faith for a long time before coming to this forum and telling us about yourself, it is good to build up more knowledge of your new spiritual path, and become a lot more comfortable with its key tenets, practices, attitudes, etc. In this way, when you tell others for the first time that you have adopted Hinduism as your faith, you won't be bombared with questions that you can't answer (e.g. Is it true that Hindus worship millions of gods? Does that mean you'd worship a cow if you saw one? Where's the weird dot Hindus wear on their foreheads, then?). There will be plenty of those - some can be very crudely put by the way - so it's not a bad idea to be fully prepared, mentally and emotionally.

In my case, I waited well over a year before I told my folks about my change in faith. They must have had an inkling for some time though, what with my open shrine to Ganesha and the rudraksha beads I'd wear around the house sometimes. Dropping very very subtle hints (like citing a new compassion for living things as a reason for your vegetarianism) might be a useful heads up for your family.

May Ganesha remove these obstacles that might hinder your dharma.

Om namah Shivaya