Exams
My exams start next Friday, so that mean that I'm nervous because the first exam is math and I know that If I study hard I can do it but sometimes math is difficult for me.
My exams start next Friday. That makes me nervous because the first exam is math. I know if I study hard I can do it, but math is difficult for me sometimes.
It doesnt really sound right how you said some things so I changed it. Also, you need to be careful to avoid having a run-on sentence.
Also
Exams
My exams will start next Friday, so that makes me nervous, because the first exam will be math. I know that If I study hard I can do it, but sometimes math is difficult for me.
Exams
My exams start next Friday, so that mean that I'm nervous because the first exam is math and I know that If I study hard I can do it but sometimes math is difficult for me.
Exams
My exams starts next week Friday, In other words i'm nervous...This is because maths is my first exam..i know that if I study well I can do it, but sometimes I find maths difficult
Exams
My exams will start (commence, begin) next Friday, so this is making me nervous, because (as) the first exam is going to be math. I know that if I study hard I can do it, but sometimes math is difficult for me.
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¡Suerte! :)