I'd go to a good bottle shop and pick up a couple of bottles of commercial Am. Brown Ales and Brown Porters to get a good idea of the spread of those styles. Then, taste yours and see how it stacks up.
FWIW, The citrusy late hops (granted - half oz additions are somewhat small for most recent Am styles, but still there are several of them in your recipe) makes me lean towards Am brown ale too. The crystal and somewhat small amount of carafa aren't enough to hit into porter, and in my experience, even hoppy brown porters can sneak into Am. Brown without getting docked very much for too much roast. Flavor wise, that upper roastiness boundary for Am. Brown is a fuzzy line to draw, since the judges tend to get distracted by the hop presence.