Hmm... Too early to decide whether this fic will amount to something or not. Not very original so far. But good nontheless.
One thing: the proper form of Headmistress last name should be Mikhailova. Mikhailov is the masculine gender of it. Assuming, of course, that she have Slavonic (Russian) origins. Also, first name Silvia is not used in Russia (and were not used centuries ago), rather it can be quite common in more western Slavonic countries, but in such case last name Mikhailov(a) has no sence.