Traditionally, when a couple become engaged the mothers break a plate.
oh. I thought it would be strange asking whether you are breaking a plate since the answer would naturally be no.
Can't it be "Did you break the plate?", which would seem much more viable to say in normal language. It's not like usually there's a plate breaker, whose role is to do so (unless it is the mother after an engagement as NaftaliFri1 stated).