the first meat to introduct to BB are fish and lean chicken breast.
i think you can try fish on your BB and follow the 3 days rule to see if any allergy. my BB has been eating fish congee (mostly sole/salmon since the bones are large and easy to pick, need to double check even if you buy fillet, especially if you buy from park'n) since 6 months.
i just mash the fish fillet and add to congee with vegi (any vegi you usually add to congee, not just tomato). sometimes, i'll steam the fish first with shallot, or garlic, or other herbs, just to expose her to different taste.
my BB didn't like it for the first couple of times, then come to love it.