There are understandings to be had with elder/younger scriptural observations. But the age of accountability is not only false, but can be dangerous.
How so? IF for example, we say that every person under X age is saved by virtue of their age, THEN logic would and has in some cases, dictated, that it is not bad if such lives were terminated in order to "secure" heaven as a surety, for children. The tempter has used this on more than one mother or father to perform horrible acts.
And likewise, using this dictate, it could even result in abortion being seen as a just thing, assuring heaven to such, aborted. This actually makes abortion "just" to that extent of "guarantee." On this basis alone I reject the notion that a young person is justified and then, at some age of accountability, is potentially or assuredly "lost."
It doesn't make any sense.
There are vast realms of scriptural data that reside in elder/younger studies that are not hinged to age of accountability whatsoever. These would be along the lines that Paul laid out in Gal. 4:29 & Gal. 5:17, showing we are all born natural or flesh people first, which is the hingepoint of the "elder" vessel, with the Spiritual coming after, or later, younger.
When God observed that the elder shall serve the younger, this was the meaning of these observations from
Romans 9:12 and
Gen. 25:21-23.
And beneath this there are still other 'layers' of understandings, for example the nation of fleshly Israel compared to N.T. believers. It is a similar example. Even in the first covenant and the second, a similar light is shed. It's quite remarkable, actually.