If your batter was in the very front of the 4' x 7' batter's box, the location of the plate becomes immaterial IMHO.
Why would your opinion be contrary to the rules and guidelines published by every baseball or softball organization on the planet?
Which rule (and associated FASTPITCH rulebook) do you believe states that a pitch that hits the plate AFTER IT PASSES THE BATTER IN THE STRIKE ZONE cannot be called a strike?
All of them! Which fastpitch rule book do you think says a pitch touching the plate CAN be a called strike?