Which one is correct?
I passed all my exams in one shot.
l passed all my exams in one try/ my first attempt.
Thank you so much for your reply.
I don't think "in one shot" fits here either.
I passed all my exams first time.
I passed all my exams at my first attempt.
Note that neither of those mean that you took all the exams at the same time (just in case that was what you were trying to say).
I passed all my exams in one go = I sat a lot of exams all in one day and I passed them all. It doesn't say whether it was your first attempt or not.