I don’t believe it’s possible to have sexual activity with a child and have it not scar them as an adult unfortunately. There’s no real way to prevent them from feeling taken advantage of, because looking back on that experience as an adult, you see that you were just a curious child and someone took advantage of that which can really ruin your trust with other people you are supposed to feel safe around.
It’s why a lot of CSA victims become social recluses because subconsciously they distrust others, even if they can’t place exactly why until they’re older.
There’s a reason why pedophilia is viewed the way it is and that’s because across the board, we know psychologically your early ages determine so much of your thought process about the world, and having an adult do an activity with you that only adults do to make a baby (this is evolutionary psychology here), only to do that for their own sexual gratification (and anything done for the child’s pleasure is also for your own gratification) they feel used and a deep distrust in others when they get too old for the perpetrator, or once they’ve figured out themselves and their likes and dislikes and sexuality, they become disgusted because they would have never consented to that person, due to their unattractiveness or any other factors one might have in deciding a sexual partner.
In a perfect world children are forever young and I can cherish them and please them but unfortunately that’s not our world