Will my action be considered sexual harassment?

I masturbated in a swimming pool while looking at my female friend. At that time, I was 16 years old and she was 14. Nobody saw me doing this. Later, I told this secret to my friend whom I trusted. One year later, he told my secret to her, betraying me. I am sure she did not feel harassed because her behaviour towards me did not change. She continued to talk to me as before. When her brother (17 years old) came to know, he beat me. Important Points: We were all minors at that time. She did not see me masturbating, and I did not tell her about it. She found out because my friend betrayed me. She came to know after one year. There was no change in her behavior, which shows she did not feel harassed. Her brother has already taken revenge by beating me. Will my action be considered sexual harassment? Can we make agreement that she will not file case against me for masturbation, and in return, I will not file case against her brother?