It's very possible nothing would have changed, but I think a small mistake here has been the fact I said “lemme know” when actually she said “we can go one day”.
We've only talked a couple of minutes in person, saying "let me know" was way too high risk with a girl who's very busy and in demand.
I should have tried to set a date right there and then rather than trying to play it cool

.
Not many chances to get anything now, but how would you move, considering that not only she hasn't replied but she hasn't even read my last message.