1990 190e mercedes key wont turn ignition!. Helpi have a 1990 190e mercrdes and the key i think has been grinded down just a lit

HELP.i have a 1990 190e mercrdes and the key i think has been grinded down just a little and now the key wont turn the ignition it only unlocks the doors. the passengers door opens fine but the drivers door needs a little jigaling to get the key in to unlock it i think this is the reason for the key being grinded down but what would be the best and cheapest way of getting the car going again i was thinking if possible taking the passengers door key hole out and seeing if a locksmiths could get another key cut with that. any suggestions!

is it a square adged key like a BMW! If the edges are rounded off it wont work. It may be a simple as getting another key cut.