At this point, it could be either. Mine was supposed to be a male, but now that it's bigger, it's very obviously a female. A few things to look for, but are not solid tell-tale signs, are a white spot between the ventral and anal fins - this is an egg spot - although some young males will get this too. Females also can have fins that are rounder, although, so can some males. Males tend to flare at their reflection, and when they do, will have a beard. Although, some males don't really care about reflections and some females will flare at reflections too. Males will make large bubble nests when they are ready to breed(they are the ones that care for the eggs and the fry), but some males don't. Some females will too, but they usually are not as big as the males (my girl blows bubbles around the edge of her tank, but not huge nests). Sorry, I know that's nothing definitive, but it does help, and as your fish gets larger, it should be easier to tell.
As far as the physical features, I really don't know much about that.