I remember you ( I used to post as lori_g2000), sorry to see you are having to go through this. I think you are right to question and right to not panic. Knowing what we all know, if it were me, I would push for an aspiration. You may wish to seek a second opinion, too. SOunds like the doc gave you good clinical opinion about
what the film showed...whereas my ultrasound showed the opposite....it showed texture, irregular density and irregular edges. From the film, they determined it to be "Highly suspicious of malignancy". sounds as if yours is right where we want it...but we all know nothing is for sure till we look at the cells. I would encourage you to get another opinion, not as an insult to the first doc, but to be sure. IMO, any doc who is decent would welcome a second opinion.
Take copies of your films and go for it!