What do I do?? With her and this situation?

Ok well… To put it in perspective for you guys is that… Exactly a year ago I went on holiday with my family abroad… And I never was with my family… I was just with the friends I’d made there… There was only 4 14/15 year olds (I was 1 of them) ther was another guy and 2 girls.. Anyway… We all became really good friends and me and this girl hit it off automatically… She would always then just blow kisses, sit on my knee, run her hand thru my hair, stuff like that, then eventually it became more… We would go behind sheds and makeout… Go to eachothers apartments and makeout and do other stuff. Then ther was this whole thing with her older bro… Him walkin in on me and her making out both with no shirts on (she was in a bikini anyway but still) and he beat me and held me under the water in the pool… Sayin he’d kill me if I didn’t stop bein near her. (I ignored him) But then after a week (ino short time for doin that kinda stuff) and when I told her I was leaving to go back home she was in such a state… I never knew she cared that much… Then eventually she let me go… (she held so tightly…) it was like I was tearing out her heart and I was tearing hers (very soppy thing to say but im painting a picture) We emailed for a few days after I got home… But it was never the same… We ended up completly stopping… But its been exactly a year since we’ve been together… And it might sound stupid but I miss her, the way she would kiss… Just everything… My friends (that know) say how stupid I am… And that al they can say is that since her bro beat me that I was “in an abusive relationship/friendship” but I wasn’t and they said to have left that second… But I just want to know how to get over it… How? What to I do to fully move on?