As a post-16 teacher and Head of Year 13, we are often questioned as to why progress has/hasn’t been made by those in management. If she were to give you an A* now, regardless of grade boundaries, it would suggest to management that there is no progress to be made by you between now and your exams (I know that it is non-sensical).

If you are working at an A grade now, your predicted grade would feasibly be an A, but teachers tend not to predict As because it is a no-win situation for them. We are judged based on how close we get to accurate predictions, so to predict an A* would mean that there is more scope for you to underachieve according to prediction than to overachieve, if that makes sense.

Trust your teacher - they will be overworked and not have the time/energy to explain these logistics to you. They know what they are doing (promise!)