Thinking too long about mc question

[cevap]

Ive been doing a lot of vcaa exams and in the last 2 exams ive have gotten 39/40 because in the core originally i have the right answer but after reading over the exam after i finish i change it and get it wrong. This only happens on core and is really frustrating are there any tips to avoid this, anyway of getting myself to believe my original answer is right? and not second guess myself.
Thanks

[LiquidPaperz]

theres not really much you can do, looking at it from my perspective. the only reason you would change is if you didnt know the question well enough, maybe look back at that area again