Hi there
You will probably have to set your exams when they’re held, and I don’t think you’ll be able to sit them early as there’s a specific marking period and the test papers need to be made etc . If you don’t feel ready, just set them in the main series and you can probably set them in November time, but it depends what subjects and you would need to check with your private exam centre to find out if this is a possibility. Wishing you all the best of luck.