This is a patient-to-patient forum, not a doctor-answered forum (though there are expert forums on MedHelp where you might pose your question).
It might be that your chances of conceiving are about the same as any other 39-year-old (which are not super-great whether or not you have had a recent surgery). But it seems that the real issue after such a major surgery is not conception as much as the pressure that pregnancy puts on your body's systems as it progresses. Obviously after a major abdominal surgery, especially if it removes part of the stomach, there is the risk of scarring and adhesions, which have implications if you had a growing uterus -- the stomach gets pushed up quite a ways! And depending on what was removed, there would be the question of how well the rest of your internal systems would cope with the heightened blood pressure and other systemic pressures of pregnancy. In short, maybe the surgery won't affect your chances of conceiving at 39, but carrying safely to term is another big question.
Really nobody except your own doctors can advise you about these issues ... they know just exactly what was done, how you have recovered, and what your body looks like (internally) now.
Congrats on making it through that tough surgery, and I hope you get your wish!
I would say your best off scheduling an appointment with you GYN doctor and discussing it with them. They will know exactly what risks it carries with it. Sorry I don't know your answer but I think this one requires a doctors discussion. Good luck and I hope you get the ok to get pregnant.