not really. I don't want to discredit the people who take them, but GCSEs are pretty low in difficulty compared to most 10th grade examinations from other curriculums.
nah computer science is REALLY easy at gcse almost every paper is set like the past papers juts learn how to answer the questions and you're solid even with basic knowledge
You'll be fine, do your best and if they dont go great it may seem like the end of the world but you can fix shit (trust my alevels went way worse then i wanted/expected)