>
> Is it too early to start meat at 4.5 months?
> Is his digestive system ready for it?

Meat is very easy to digest. Lots of people uses harder to digest
things like grain and vegetable concoctions that are much more
different from milk than is meat. Milk is a high fat high protein food.
So is meat. Start out slow. One bite is fine for the first few
feedings. At that age my daughter loved to chew lemons!  and other
fruits. I don't think it is too early, if the baby agrees! Japanese
give fish broth and small bites of very soft fish.