If it were more definite I'm sure some additional views or other type of investigation would have been recommended. If you are terribly concerned you might ask your Dr. if an Ultrasound would be a bit more specific. This could be only a shadow on film representing normal lumpiness of the breast tissue. I would think the 6 month follow-up is being done to demonstrate any change in the area. You don't state your age and that could very well make a difference in the opinion expressed in the report. This may be the very same finding that was mentioned on your Mammogram 1 1/2 yrs. ago and represented no change. I personally would go with the 6 month re-check or the Ultrasound if your Dr. isn't satisfied with the vague results. There would normally be more information contained in the actual Radiology report on your film so you might obtain a copy of that and see if there is more there. Regards ...
I think waiting 6 months is okay. Why have surgery before you need it if at all. If it does turn bad it will probably be in early stage and maybe you won't need chemo, especially if you are post menapausal. Make sure to do your self exam at the same time every month.