Minor consideration -- and this is just me being a drunk nitpicker who wouldn't give a shit except I used to write like this when I was younger -- I think a line like this:
"If I recall correctly, our arrangement was for you to come over on the weekend"
is stilted and ought to be replaced by
"I thought we agreed you wouldn't come over until the weekend?" or maybe "I thought you weren't going to come over until the weekend"
Other nitpicks / matters of taste:
Think "so don't expect too much, alright?" is also a tad awkward, might replace with maybe "so don't get too excited, OK?"
Similarly, I might change "...Somehow it's really embarrassing, so turn around, Umi" with "Turn around! It's embarrassing when you stare at me, Umi..." or something more like that.
But, I mean, I'm anal-retentive like that. Feel free to ignore as necessary.
Strongly encourage you to start qcing things if you don't already do that somewhere else.