You are understanding me correctly. I am saying that from the point of view of Justice for Children and Youth, a rebuttable presumption is preferable to an absolute rule, because we are all trying to prevent exploitation, and it's hard to get hold of, so we use age as a proxy, not because we actually know for sure it's exploitative.
In our view, the autonomy of young people must be recognized. Their individual rights—If they are not being exploited, if there is no exploitation, then it shouldn't be a criminal activity.
So we would prefer a presumption that would allow for young people who mature in different ways in different circumstances. Some have less emotional maturity and greater physical maturity. Some have greater intellectual maturity. They develop in different ways at different times, and if we're trying to get at the heart of their individual sexual relationships and not criminalize behaviour that was not exploitative, not manipulative, not part of a power imbalance, then that is denying the autonomy of the younger person.