I can reject and dismiss any child's application for Church membership, because there's no such thing as a mature child. I've never heard of a mature child, have you. The Lord Jesus Christ was still Jehovah God at the age of 12, when He taught in the Synagogue. So you can't use Him as an example.in Luke 2, how old was Jesus when He was dialoging the scribes and teachers in the temple?
12 - a year before the Jewish coming-of-age.
now, as an human He is extraordinary - a man in which there is no sin, the likes of which was never seen since Adam - but why do you suppose He put in His book this record? why is it there specified He is still a child?
there are any number of things we as adults do not understand, but still believe. perhaps all things, ha!
so i would not be so quick to dismiss children in the way you have.
So I can dismiss the "mature child" myth, because there's no such thing. You can't be young and old at the same time