sounds perfect to me! a good ten year difference works. A good amount of conflict and challenge always makes it better. Kieran definitely knows how to mix it up. He can even be the type of student who took her class that wasn't her most promising but showed definite skill? Just so he's not immediately recognizable, that could be fun to play out as well.
I'm about to call it a night, but I'll be on aim tomorrow if you want to get started or threads if it works better?