I mean, if I was reading the book I would be wondering the same thing.
And it would nag at me.
Which is totally unfair.
Now, there are some specifics to that question which will be addressed in book two, Stone Crossed Angel, so I will leave those out for now. That, however, doesn't mean we can't have some insight now.
Think of angels, any way that you see angels. They can have wings, fly through the air, play the harp, and have golden halos if you'd like, it really doesn't matter . . . this is your vision. Okay now, let's say that your angel had taken a particular interest in you, even going so far as to say that angel was your guardian angel. (This doesn't mean Maura was Brandon's guardian angel, FYI, this is just to get you thinking and see my train of thought where angels are concerned) Now with this angelic interest, don't you think your angel would be seeing you in relation to the world around you? For example, if they were to see you driving a car, they might not have experienced a car in their lifetime, but they'd come to understand what it was, right?
Okay, okay, so take that information, and place it within Maura. She doesn't remember specifics of her life before she walks out of Bonaventure Cemetery that stormy night, but that doesn't mean she wouldn't find her surroundings familiar in a sense - or at least have an unspoken understanding of what things are, how they work, and of course, how people talk.