Glad you have the appointment - though not so great that she didn't ever tell you about it...!
As you say, maybe it's better that you don't have too long to see it looming ever closer on the horizon. Try not to think about it too much - easier said than done, I know, but it sounds like there isn't really anything you need to prepare. Just try to see what comes up :-)
Hope it goes well and that her response to the writing you gave her last time is reassuring for you. I guess it's possible that she might not mention it as she might wait for you to do so. So perhaps just think about what you want to do if she doesn't refer to it. It probably won't mean that she's forgotten about it, just that she's leaving the ball in your court. So maybe if you want to discuss it and she doesn't bring it up, you just need to have your line sorted beforehand so that you're comfortable about bringing it up yourself.
Hope you have a good session.