Memory or Fake?

I...have no idea if this really happened. Okay maybe that's a lie but I was a little kid and yet I can remember a lot of details.

I remember laying in a bed with someone - maybe a kid close to my age at the time - laying in my bed and forcing me to touch his privates as we laid under my blanket. I remember how my walls weren't yet painted and how my twin bed still felt big to me. I remember feeling scared and confused and told to keep this a secret or I'd get in trouble. I remember my step brother at the time finding out about it and threatening to tell my mom and I was so scared I just ended up crying and constantly changing the story when confronted. I remember that some time later, I started getting into the habit of locking my door, even as I fall asleep even when I know that's not safe because what if a fire or other danger would happen?

Even in a new house, a new room, a new bed, I can remember details even as some shift around and confuse me yet I'm not sure if this is a memory or if my mind is just fucking with me. Because what if I'm wrong? or worse, what if I'm right and either way no one would believe me?