Got kinda intimate with my legal step sister as a minor…

Little bit of context, I’m 19 now and all of this happened when I was 14-15 and she was around 19. My step sister moved from Germany to come stay with us in the United States, this is also one of the first times I met her. As time went on we got closer and closer until we started watching movies together in her bed, that closeness slowly turned more physical but we never talked about it, I was 14 with raging hormones and I used to touch her chest inappropriately and she wouldn’t stop me, in fact we never spoke about what we did we just acted like it wasn’t happening, even with each other.there was a time when she kissed down my neck while we were cuddling and one where she “fell asleep” with her head in my lap and happened to turn on her side. It all came to an end when one day she handed me a letter and didn’t say anything. She said that we should stop and that what we were doing was wrong, and that was the end of it. We never spoke about it, what was wrong was never truly acknowledged it was implied, and to this day we still act like none of it happened when we see each other