There are lists of signs that combined can indicate a child undergoing or having experienced CSA. In my own case, this screemed out for years...alcohol use, bedwetting, fire starting, scab picking, loneliness, various acting out (fights, school trouble, sexualized behavior), compulsive masturbation, porn addiction, inability to form close relationships, risk taking, depression... I was in therapy in college, majoring in social work and although both my therapist and myself agreed something had happened, we could not identify it. Finally, at age 42, I started remembering whether I wanted to or not. We listed a number of events in my life as likely abuse periods. One of the periods was a summer trip to an uncle's that ended with our mother fleeing with us. I could never remember anything that happened on the trip itself. Turns out the entire trip was a nightmare, my brother and I had been kidnapped by a sadistic pedophile.
The entire time I was growing up, I was in therapy for behavioral problems. But the entire time, I was diagnosed as ADHD and everything was explained with this diagnosis. Nobody bothered to check my butthole after returning from the summer trip.
Long story short, there are lists of signs that can indicate sexual abuse. Any one of the signs can occur in other situations, many entirely normal. However if you are asking is it possible that something happened to you and you can't remember it, the answer is yes.
God grant me
The Serenity to accept the things I cannot change,
The Courage to change the things I can,
And the Wisdom to know the difference.