I agree, fresh is so much easier than frozen! Frozen takes forever and a day to thaw (even after an overnight in the fridge it's still mostly frozen!). And less "contact" if that's an issue. I also agree that you need to confidently tell her how it's going to be. It's not a question and if you project uncertainty, you're opening it up to debate. You're not uncertain. This is how it's going to be. You can be firm while still being super nice and appreciative. If you get put on the defensive, you're immediately at a disadvantage.