My first experience of sexual trauma (that I can remember) was when I was five. The perpetrator was my eight-year-old male cousin. The encounters weren’t violent and happened at nearly every family holiday gathering for years.
The fact that there were so many adults just one room away left me angry and confused. For a very long time (I’m in my 30s now), I couldn’t understand how I wasn’t to blame because there were so many adults close by. I have also struggled with wondering if it was consensual because he was also abusing several other female cousins, sometimes three or four of us at the same time at these family gatherings. He would abuse us one at a time while the others stayed in the closet until it was their turn. The abuse itself was posed as a game of “playing house” where he was the daddy and we would take turns being mommy.
Knowing his childhood was traumatic (arguably more traumatic than mine) also added to the confusion.
Child-on-child sexual abuse is defined as:
“A single or repeated encounter(s) between prepubescent children which involves sexual abuse by one or more other children, and in which no adult is directly involved. While this includes when one of the children uses physical force, threats, trickery or emotional manipulation to elicit cooperation, it also can include non-coercive situations where the initiator proposes or starts a sexual act that the victim does not understand the nature of and simply goes along with, not comprehending its implications or what the consequences might be” (Shaw, 2000).
When I read that last statement, “does not understand the nature of and simply goes along with, not comprehending its implications or what the consequences might be,” a feeling of relief and forgiveness for myself came over me because I distinctly remember being confused by what my cousin was trying to do the first few times, and then started hoping we were really going to play house this time, to eventually just accepting what was going to happen at each family gathering.
Child-on-child sexual abuse is differentiated from normative sexual play or anatomical curiosity and exploration (e.g. "playing doctor") because child-on-child sexual abuse is an overt and deliberate action directed at sexual stimulation, including orgasm (Loseke, Donileen, Gelles, Richard, Cavanaugh & Mary, 2005).
There is a resounding acknowledgment that victims often have distorted recall of the act, such as thinking it was consensual.
The fact of the matter is, this person contributed to the loss of my innocence at a very young age. I may have only been five years old, but I know in my soul I wouldn’t have initiated any of that. Sadly, I just wasn’t skilled, mature, or confident enough to resist the abuse, much less verbalize it to any adult. That doesn’t make it consensual. One time my aunt (a negligent person by all accounts) walked in on the abuse and simply said “cousins don’t touch each other like that, now go play outside.” I was left in mental turmoil; that statement didn’t make it consensual. When the abuse went to a whole new level in my teen years, that didn’t make it consensual. When I finally spoke up and was asked to forgive and move on for the sake of the family, that didn’t make it consensual. I was never having fun. I was never intrigued. I always felt ashamed. I always felt nauseous.
I still feel nauseous when I think of him, but I feel less and less shame as the years go on and I work on healing myself; and that makes me feel strong, proud, and in control.

References:
Shaw, J (2000). "Child on child sexual abuse: Psychological perspectives". Child Abuse & Neglect. 24 (12): 1591–1600. doi:10.1016/S0145-2134(00)00212-X (https://doi.org/10.1016%2FS0145-2134%2800% 2900212-X) . PMID 11197037 (https://pubmed.ncbi.nlm.nih.gov/11197037)
Loseke, Donileen R.; Gelles, Richard J.; Cavanaugh, Mary M. (2005). Current Controversies on Family Violence. Thousand Oaks, CA: Sage Publications Inc. ISBN 978-0-7619-2106-6.