I think the AK fold was fine.
On the second hand- well I suppose if you'd played this predictably and by the book you'd of possibly kept your place in the game...
but you know that already, and there's nothing I can say which you don't already know

You had a read on him and you chose to play it that way, if it had worked out favourably , it would of been a hand well played.
You can't be too predictable can you, and I guess that applies moreso at the level you are playing here.
I don't know if you necessarily put this down as a mistake. You can't really kick yourself for going with your read and instincts can you.