My son is in y12 at a sixth form college, not quite as big as yours but maybe 800 per year so still large. He’s already had a brief report for each subject with lesson attendance (%), class effort, homework effort (marked from 1-3, or Below, at or exceeding expectation), working at grade (based on how well they’re doing so far, many caveats around it being v early days, and it not being a predicted grade), and their target minimum grade (this is largely based on prediction from their gcse results).
We won’t have a parents evening till some time next term, I think, but the report is helpful. What is even more helpful though is that each time he gets a test or mark for anything back, he can tell us where he needs to improve, usually how that score compares to the rest of the class, and if the teacher has given indication of what that would mean for a level.
Your daughter and you aren’t going to get a clear “this is an A grade” because it’s only testing a small proportion of the course, it’s likely to be building in complexity as the course goes on, the assignment may not have been done under the same exam conditions, and the teacher likely knows it’s still uncertain. But your daughter should be able to understand what sort of test it is, what she works on next, is it a past paper question etc.