1.) In terms of plot, the base of it will center around the French Revolution. Said main character is particularly rebellious to social norms of that time (putting her in positions of danger very frequently), and in the process making many enemies and many friends, and perhaps a lover (whom can be either female or male, I have no preference in relationship type). They'll experience a near death or life changing experience that reveals "magic" and that will be used to prevent revolution and mass chaos of the country. Kind of a nice underdog hero trope.
2.) Magic is nature based, i.e. somewhat pagan. Nothing massive or life changing and little to no physical manipulation (like, no waterbending or such). If the plot calls for magic beyond these limitations I'll specify & allow :)
3.) You'd be the main character, I'd be everything else, mostly.
Also side note: the "witch" in the title comes from the fact that she is such an outlier (and the magic of course). Itd be kind of a slur in those times because accusing someone of witchcraft, well.. could cost them their lives :/