I've been vegan for about 4 1/2 years now. It took me about 18 months to transition from a fairly carnivorous diet, through vegetarian, to vegan.
I have a good friend, who has been vegetarian all his life and vegan for about 9 years now, while I still ate meat I used to respond to his vegan FB posts or comments with stuff like "Mmmm, bacon" or "but it tastes good". But slowly, embarrassingly slowly, I began to realise my "I love animals" comments were in direct conflict with my "mmmm meat" comments, and that my responses to my mate's posts/comments were pretty disrespectful and infantile. That realisation triggered my journey to veganism.