At the age of 13, there is a very good chance that your breasts will diminish in size as you continue to grow and develop.
The size of the areola is not, by itself, an indication of Gynecomastia. At least not in terms of diameter; projection would be an issue but not necessarily diameter alone. I think this would be more a hereditary thing.
I too would like to know if your size is a family trait or if you are significantly larger than others in your family.