Can anyone help me predict what it will be like coming back?

I used to event very competitively for a couple years and rode around twice a week at this barn. I had to stop riding due to leukemia, but now that everything is all good health-wise a year and a half later, I'm returning to the barn. Can anyone help me predict what it will be like coming back after that much time off? I'd been riding my whole life and have no idea what to expect. I don't want to expect that I'll be ready to be jumping 4 feet on my first day back or be frightened to return that I will be completely off balance with horrible form at a simple walk. I know each case is different, but anyone's stories would be appreciated!