hi there, i'll do my best here as there are lots of things that are missing, but that's ok, I appreciate you are not too comfortable saying too much about what has happened, and that's fine.
my first question to you is what does this person feel about you? I think it would be a good place to start especially as you are still able to talk comfortably about things. make the most of that if you can, as not everyone gets to talk to people who are rational or responsive for whatever reasons.
I think once you know if she has feelings for you then that will give you more to consider. she may actually still like you but is not bringing it up because she doesn't want to make things uncomfortable if she doesn't know how you feel about what happened and how you feel now.
is she still single? or are you madly crushing on someone that is no longer available, and is that why you don't know how to "end" this?
what is the danger for you if you go forward, (I don't understand) do you mean if you tell her how you feel and you have a proper relationship with her it will be a problem for you or your families?
I think it would be best if you can to talk to her "a.s.a.p." so you know what is what in this situation. by not talking to her you are letting things get out of control even more and they already sound as though they are in fantasy in places because you are guessing what she might feel or haow she might react when you dont actually know for a fact, also if this goes on and on, any fantasies you may be starting to get into however harmless now could get more obsessive (and then you will only be getting even more hurt again) if after talking you find she doesn't actually feel the way you still do after all this time!
you say you want to move forward, do you mean move forward with her as a couple? or do you mean move forward and forget her because you are frightened of what she might say or feel?
I think you are confused because you don't know what she is thinking, you are guessing and imagining what might be, enjoying what was, but are scared that things may have changed but you cant be sure. if you want to stop all of this confusion then you HAVE to talk to her.
when whatever happened happened, did she ever tell you that she was unhappy about what happened, or that she didn't want to see you again or that she just wanted to forget things or maybe cool the relationship or friendship?
if you do talk to her and she tells you that she doesn't want you in the same way you clearly want her, then I think that you'll just have to respect what she wants and try to not let the intensity of what you feel damage your friendship.
you clearly have strong feelings, but they are no good if she doesn't feel the same way or is at least willing to give you a chance for a relationship: if this thing can ever go anywhere for you two.
the last question is is 300km going to be too far or is it a realistic distance for you to keep a relationship alive if she does have feelings for you and wants to get together?
ok, I hope something there might help you, but if I'm being honest, I think you already know what to do, its just that you are looking for outside permission to get in touch with her and find your courage to say what you feel you have to to her.
so go for it...why not, take that step forward and talk to her. of course no one can guarantee things will turn out as you want, (even if you do get together in the end); but you would at least know where you were.
it might be better to send a letter and put all your feelings down that way rather than actually going to see her, it could be very disappointing for you if you went all that way if you then find out she isn't interested anymore or was seeing someone else!
maybe why not get in touch with her in writing and tell her you'd like to meet up with her as you have something to say to her, and ask would she be willing to meet you etc.
reassure her that its nothing to worry about or she might be anxious for no reason, but I think you need to talk to her and soon.
how would you feel if she liked you but was tired of things not moving forward with you, you would come away feeling even more regret and hate for yourself for not dealing with what you know should have been sorted out and discussed years ago!
good luck with this, and if once you've spoken to her and for whatever reason it doesn't work out, then at least you can start to get this out of your head and let go of this situation. don't beat yourself up too much for being weak now, I suspect she knows you well enough to know that you are weak, but she is giving you a chance to put things right between you both. its not the best thing to be weak but we all have areas that are not as strong as other bits of ourselves, but hopefully, once you can talk to her it will help to control that weakness in this area and will give you the strength to find out what the truth really is now.
she sounds like a pretty smart person who has given you a chance to come to her to talk, so don't let this chance go again or you may not get another with a girl like this.
what I will say again to you is: "if for whatever reason she is not interested. then you MUST repsect that and let her go". otherwise you could be in danger of really getting how you feel out of control and getting into areas that are not healthy, and she may keep you at a greater distance permenantly!
she is willing to talk to you, so make the most of that. if you cant talk to her now, you are really going to struggle i think; particularly if you do get back with her and something far more serious comes up.
you have already put yourself in a depressed position over this because you have been fearful. if she is the fair, open minded person I feel she is then she at least desearves to know how you feel and what made you act the way you have done (good and bad).
good luck. let us know how it goes if it goes well. I hope it does, but if not. you tried and that's the important thing.