OK. It feels really weird. Given the way Rei is introduced as someone you just met, without having just met them, it's a bit odd. At the very least, either the flashback would serve better to be immediately after the introduction, or just to be phrased differently (like not making such a strong point about having just met them before). That's my take anyway. If I had to choose one to recommend, I'd say moving the flashback closer would possibly be easier and more effective (if you wanted to worry about it, otherwise just a note for future projects maybe).
I do have to say I've enjoyed it so far, and also quite the Reboot Love games too (been looking forward to more of that).