OK, so this may be a little strange

I have some unresolved trauma I'm realizing from my childhood (attempted assault-ey type stuff) but we were both kids and I believe the other party had had some things happen to them and they hadn't processed or didn't understand it was wrong. But they got mad I told my mom and I ended up losing my only friend at the time. And I'm realizing as time goes on that messed me up in the sense of manipulation and how I've been susceptible to emotional abuse and manipulation since then. So..how do I get closure? I don't want to reach out to the person unless I know I need it. But how do I know and is there anything else I can do for myself to help get closure before I potentially open that door?