I think you should wait until you're in the course and see how it is going? Since it doesn't start until next month and, presumably, takes a little while, you can see how you're feeling then, you may feel completely different about the whole thing.

If T brings up the course or graduation or anything about it, I'd get a little sarcastic :-) and explore it with a bit of a joke, "My, aren't you anxious about this course I'm taking, Mr. Mother Hen?" and see what develops. But until I started the class and knew how stressful it would be and whether I'd like it and be able to finish it or not, I wouldn't worry about the graduation ceremony quite yet?

I would give yourself permission not to like/want to take/finish this course! It might be too soon for you or not your "thing" or you might want to find your own "sort" of course. But I think your T is going a bit overboard with his thrilldom that you are taking this course and that's setting up a bit of anxiety on your part, wanting to "please" him but having your own second thoughts (or you wouldn't have "forgotten" to tell him). Always go with what you feel and want, you are all you have, he can't take, enjoy, or benefit from the course for you.