Andy,
Asking if MDS has been confirmed, and for a more specific diagnosis is certainly a starting point. You could also ask if your MDS has been scored under one of the classification systems and where you fall on the scale. Those are broad categories but they usually influence the decision-making about treatment.
The most important question is what the doctor recommends, e.g., a wait-and-watch approach, transfusions, drug treatments, or something else. I'm sure you'll want to know not just the recommendation but
why the doctor favors it compared to other choices.
Patients can't be blamed for wanting a specific prognosis and to know just what to expect, but the doctors can't tell you with certainty. What they know is based on the statistics across many patients but MDS is a complicated set of diseases so every case is individual.
I suggest that you ask the doctor about anything he or she says that you don't understand, even if you have to interrupt. We're all tempted to nod our heads when the doctors explanations are above our heads, but you'll both benefit if you ask for clarifications that will put you more in sync and make you and your doctor a team. The best doctors prefer a conversation to a lecture.
If you'll need treatment, you'll want to know what kind, how it's administered, when you'll start, what the risks or common side effects are, etc.
What's most important is that you ask the questions that are on your mind, because everyone comes at it from their own perspective. It helps a lot if you write a list of your question ahead of time. Otherwise it's easy to forget. If someone else can come with you to the appointment, they could take notes or help you go down your checklist.
Here is a set of questions that the Aplastic Anemia & MDS International Foundation gives as an example.
It won't be the last appointment so you'll have further chances to learn and ask questions, but I hope your first appointment goes well and gives you assurance that you're in the right hands.