I answered your question and presumed you would answer mine, which was very simple and precise. I was wrong. I will learn to not waste my time in the future.
I feel like I did answer your question. Within the Gothard cult that Josh was raised in, confessing would be a more normative behavior for a 15 year old. My opinion is based on people I knew within the cult and what I have heard the Duggars say. They are trained from a very young age to do that.