Made my post while lots of other posts happened in between, including you saying you were going over the past. If you are doing this with a therapist, that probably is the best way to process it. In my opinion the age (especially maturity) of the minor makes a difference, but that is not what the law says. Like I think it is crazy that two 17 year olds cannot have sex and that therapists are required by law to report this activity. Likewise what if it is sex between someone 19 and someone 17? Is that abuse? So I have reservations about many aspects of this issue, but I do understand that protection of minors is the main idea and that is a very important thing to uphold.

By the way, at least in California and this could be federal too, if you tell a therapist about past sexual contact that is reportable, usually you are fine in keeping that confidential, but if the adult is currently in contact with minors, the therapist is mandated by law to report it immediately or face a misdemeanor and losing their license. All they have to have is "reasonable suspicion" to make a report, no proof, not anything concrete, just suspicion.