This was... really difficult to asses, for me. And not for any good reason! 
 Badly Explained Plot: English people are magical animals. But not all of them. Racism ensues. 
 Okay, so, I normally struggle with beginnings, and even some of my best books I would say have slow starts. Not My Lady Jane! It had a fun start, and although it didn't leap right into the action, it was enjoyable. A strong start. 
 The middle was a good continuation. I started to enjoy the travels of one of the POV characters less than the others, but still acceptable. 
 The end was... meh. But not in a "the ending was bad" kind of way. Not at all, I'm sure most people would love the ending! What happened was, near the end, I was struck by inspiration to write my own fantasy novel, and the story I wanted to write wasn't the same style and tone as My Lady Jane, and so reading this became a slog, because my mind was elsewhere. 
 All in all, a solid read that I'd easily recommend to someone looking for an amusing and light hearted fantasy.