No, these behaviors are not normal for children, especially children so young as 6-8 years old. Unfortunately it is extremely likely that Amanda was sexually abused, and was mimicking the behavior of her abuser(s). Even her advice about how it's "your body and you can do whatever you want with it, don't listen to your parents" is absolutely insane for a 6-8 year old to say. There is no way she didn't hear that from an abuser who was manipulating her into silence, as well. Very likely she tried to assert the advice given to her by her parents that others are not allowed to touch her that way, and that's what her abuser(s) told her.

Now understanding that, hopefully you can see that as a child, you also then went on to replay the abuse you suffered.

This is extremely common with children who are sexually abused.

And yes, these experiences could absolutely be causing you problems to this day. I highly recommend finding yourself a good therapist.