Struggling with the aftermath of sexual trauma

I have been struggling mentally very much lately. I was SA’d by my step brother when I was younger and only remember bits and pieces of it. I described what happened to my mom and stepdad (years after the matter) and they supported me and confronted him. He didn’t deny a thing and also cried. So after begging my parents for a year, I went to therapy and tried to open up about it and the therapist said that they might send someone to his house. My mom informed him then he started denying everything and said that he was young and I was basically too young to remember and the SA only happened x amount of times. My mom told me this and I said I don’t remember exactly how many times it happened or my exact age and that I explained it to the best of my recollection and she said “well I guess perception is reality” after this, i was never brought back to therapy and now I just feel so conflicted. I feel like it happened so long ago and I should be over it. I wonder if there is more stuff that happened that I don’t remember? (I still have new memories pop up that cause anxiety attacks) I also feel like my parents believe him more than me. They are supportive of me but also say things like “you have to face him” at family events, they also told him that we aren’t going to tell anyone what happened(i feel like it should be my story to tell) , then also saying that what I said had happened was my “perception.” I just need someone to let me know if it’s common to not remember everything, and for new memories to be triggered later in life, or if it really is just my perception. I was confident until he started denying everything and my parents started acting funny. I feel so invalidated and wonder if my mind is playing tricks on me. If anyone has any knowledge on this, please let me know!