I never had a female in heat so I'm not sure, but it sure sounds like it. One of my neighbors is a breeder, and if I'm not mistaken I think she says it lasts around 3 weeks? Eight months also sounds like the common age for this to occur, so I'd say there's a good chance that she is in heat. Ask your vet, but I think you could probably get her done directly afterward, which should take you right up to February. Vets will actually spay them while they are in heat, but they don't recommend it because there is a greater chance of complications.