There’s no rule against waiting your turn when getting off of an aircraft. Normally you stand up, walk into the aisle either right away upon reaching the gate or when the row in front of you starts walking off the plane. And then when the people in front of you are on their way out, you proceed down the aisle yourself.
But is there a rule against squeezing through the passengers in front of you, while you’re waiting for the aircraft doors to open? No, not really.