The "age of accountability" and ensoulment

Baptists and similar strains in Protestant Christianity talk about an "age of accountability," with the implication that "not so good" behavior committed before that age isn't fully "sinful."

Well, let's take this idea a bit further.

Does that mean a child before the age of accountability isn't fully "ensouled" either? (Presuming, just for this line of argument, that such a thing as a "soul" exists.)

And, what, then, does that say about a developing fetus, one, say, before viability? Is it not "ensouled" at all?

Hmmm....