Long story cut short, when I was 15 I fell for a 27 year old woman, I lied to her about my age, saying I was 19 almost 20, so that we could keep on talking, stupid I know, but I was so in to her I didn't know what else to do, and we became really close and almost in a relationship, we were seeing for months, everything was perfect, except my lie. Apart from that lie I was very mature for my age and looked quite a lot older.

Eventually I was honest with her, and she was so mad and ended this whole thing there and then, and would not listen to anything I had to say. She returned home to her own country a few months after, all the time I was hurting and crying most nights. I thought I'd have long moved on by now, but I haven't. It's been three years and I still think about her so much, and it kills me that she has probably forgotten all about me and doesn't give a damn what happens to me, when I can only keep thinking and caring about her, hoping she's all right. Dating other girls hasn't worked since then, some girls like me and I try to give them a chance, but my subconscious keeps measuring them up to her, deeply unfair I know, but I don't do that on purpose.

You kind of have to accept the fact that you won't forget about her.

Moving on however is another thing. Try reading the stickies, from what I can gather from your post, you've been outside of contact for quite a while.

Just give it time and keep living life in a way that makes you happy. Time really does heal all wounds.

You can't expect much when you lie, and deceive, especially when a kid, can deceive an adult. That has to be devastating.

You can't replace her, but you can forgive yourself and stop dwelling on things out of guilt.

It has been 3 years it is time you get on with your life. You will be entering adulthood soon.
Perhaps it will help to talk to a professional, get some help so you can clear your mind and conscience of this, give you the tools you need to be an 18 year old and move on.