This is difficult. Second guessing, because now it is becoming so real to you.
I think the only thing I can say is that you need to trust your original decision. You need to know that the perp would not want to add to the charges, that he harmed or caused a problem to his accuser and chief witness. And, I think you need to do exactly what you are doing. Tell us about your fears, ask for ideas, let us be a support for you.
Can't think of much more just now.
If we do not live what we believe, then we will begin to believe what we live.