How to file for a sexual harassment case?

Hii I'm 23 years old male when i was 8 years old i was sexually harassed by a person who tried to penetrate he was in the same school but he was not teenager ....the reason why i could not do anything Was my lack of understanding of the matter and my family environment which was not that open that i could tell to my parents i knew that bad thing happened to me but my childish psyche didn't allowed me to share this with anybody....i want advice what action i can take now, human psychology is to get justice i think that lack of evidence can lead to no justice to me and i live in a stereotype society where I'll be ashamed if I'll open up, the evidence which i think is available can be from school side to confirm that he studied there when i was studying other than that a boy was his friend he might know about incident but I'm not sure if he will witness it so please guide me if these can be enough or there is no chance on this basis....