you're going to hear a lot of differing opinions here because so many "experts" have so many differing opinions on the subject! some say jar food at four months, some say six months. some say only one type of jar food each week incase of allergic reactions, others say mix it up but write it down. some say give veggies first and absolutely no fruit until they love the veggies, others say give them what they'll eat..... they all say so many different things, what is a mother supposed to do????
i'd say trust your instinct. i personally think my oldest would have loved it if i'd given her zwieback toast at that age, but my younger daughter couldn't have handled it! so as long as you use the mesh bag, and don't leave him unsupervised at all, i don't see where it would be a problem.