Hey, my GCSE’s are approaching soon too. I’d say it depends on wether you think you can manage your stutter in the exam or not. It’s better to not do the speaking test and still score very high in your other French exams since you seem to be good at it so you’d get a good grade overall. But personally I would go for it. Your stutter shouldn’t let you miss out on things and even if the exam doesn’t go well, it’s okay! You would walk outta that room knowing that you gave it your best go. I get it, it’s difficult to put yourself in these situations, but if you let your stutter stop u now, it’s likely that in the future you’ll back out of amazing opportunities all because you let your anxiety take over. Ultimately it’s your choice tho, do whatever you feel the most comfortable with. Goodluck :)