Seek2 and Blue Rose have offered some sound suggestions and asked some hard questions. It is very important for you to understand that you are not alone - I was a victim of sexua| assault during my adolescence and it tainted my understanding of myself for many, many years. I never told my parents, even to their dying days. But, I did tell counselors and therapists during various points in my life when I couldn't manage triggers, etc.
I would strongly recommend that you speak to a trusted adult - perhaps, a school counselor. Tell them what happened and they can point you in the right direction so that you don't spend the rest of your life like I did: fearful and feeling worthless. You are valuable. You don't have to be afraid. And, you can put it all into perspective so that you can be a stronger, wiser, and vigilant human being that can advocate for others like yourself.
Most sincere best wishes to you, my dear.
I completely understand your hesitancy to speak with your folks - I had a fear that my folks would no longer love me, think highly of me, and a host of other things that I used to avoid truthful speaking. What I want to say is that most all parents will be understanding and supportive of their children's issues, even if it takes them a while to get over the shock. As a parent, it's never a simple task to imagine my children going through misery, but they do. Speaking truthfully to your folks doesn't necessarily mean that you'll have to provide details. Preparing them with honest and carefully chosen words will help them to help you, if you ever seek to speak to them.
"Mom, Dad, I want to talk to you about something, but I want your promise that you will not interrupt me or stand in judgement.. If you can't agree to that, I'll speak to you about it at a later date." Nothing wrong with that.
Again, my very best wishes for you.