Doe, A Deer
The book closes with Gemma chasing after a deer, and the last line is:
Because I want to see how far I can go before I have to stop.
We've got all sorts of things to say about the deer over in the "Symbols" section, so you'll definitely want to click on over there, and for our purposes here we're going to focus on the fact that Gemma is running.
Guess what running isn't in 1895? That would be ladylike, Shmoopsters. Girls are supposed to wear restrictive layers and sit quietly and never sweat and stuff like that—all of which, of course, is pretty much the opposite of what happens when someone runs.
So as our story ends, we see Gemma doing what she wants instead of what is expected of her, breaking loose from the demands that she be prim and proper, and letting loose. And when we see her this way, we know nobody will be able to contain her any time soon, that Gemma will continue to follow her heart and stand on her own two feet. She wants to see what she can make of herself in the world, to find her own limits, instead of those thrust upon her by society.