You are using deductive reasoning - if A is true and B contradicts A, then B can't be true. I am saying that A is a generalization that B may not support. I am interested in getting at the truth behind the generalizations. I want to see facts, evidence of prosecutable crimes, and then see those crimes prosecuted.
Of course we are speaking only of probabilities. We do not have omnipotence. Your proposition that this is a horny teenage girl wanting to get it on with an older guy and having, not just one, but two kids, is at odds with all the known practices of the cult. Often, after kids were simply observed becoming sexually aware (simple flirting or an innocent kiss), we are told by former cult members that they were given in marriage to someone else at that point.
In other words, there is no support for your position from the evidence we have about the cult. There is plenty for the counter-position. If you want an angel to descend with gold plates with the specific truth about this situation, you will probably be waiting awhile.