It will be different for everyone, I suspect. I eased gradually in. I suppose I could say I started easing in as soon as I started eating solid food, as I live in the US so it is customary to eat many things raw: most fruits, many vegetables (carrots, celery, salads, etc). As far as eating raw meat goes, I had my first taste of sushi with raw salmon back around 2003, and that was also the year when I first began experimenting with eating raw muscle meats from mammals. I started with goat (I really like goat), and expanded into sheep, cattle, deer, elk, and bison soon after.