A 33 year old woman is too old for a 23 year old guy. I am assuming you are the male, and so I say: she should have known better. Tell her you enjoyed your time together, and that you have learned a lot and will never forget her. Then let her go back to Japan.
(And no, sorry... I did not read the whole thing... pretty much only the first and last paragraphs of the 1st post, and the entire 2nd post.)