Fantastic Beasts' Professor McGonagall Plot Hole Can't Be Fixed

So how, exactly, is it possible that Professor McGonagall was running around Hogwarts telling off students in the early 20th century, if she was born in 1935 and started teaching there in the 1950s?
Read more: https://screenrant.com/fantastic-beasts-mcgonagall-plot-hole-solution/?source=Snapzu