She is leaving New York at the end of the summer. You have twenty-one days.
Each day you may do one thing — write, wait, send, suggest. Each evening you make your diary entry: how likely is it, honestly, that she would say yes?
Somewhere in those twenty-one days you must ask her the question. Ask too early and the answer may not yet exist. Ask too late and the train leaves with it.
At the end, your diary will be compared with the diary of a perfect statistician who saw exactly what you saw. One of you was in love. It is not obvious which one read the evidence better.
Tomorrow the twenty-one days begin. Nothing has happened yet. The summer has produced no evidence at all — only her, at Milena's party in June, laughing at something you said and then, crucially, at something you didn't.
So before any of it: your prior. Honestly now. If you asked her now — before doing anything at all — how likely is a yes?