is this possible? i mean, i'm a reasonably healthy person, and a smoker. i've never heard of anyone getting lung cancer at this age. is it even possible? i mean, of coarse its possible, but is it likely?

The chances are very very slim, so slim I wouldn't worry now but I'd try to quit for as each year goes by your risk will increase, not only for lung cancer, but throat cancer, tongue cancer (which really sux, try and talk with no tongue) heart disease etc. Once you kill the fine hairs in your lungs that help you stay well, they never grow back.