YOU SAID:
I have board exams in 13 days
INTO JAPANESE
私は13日でボード試験を受けています
BACK INTO ENGLISH
I am taking the board test in 13 days
INTO JAPANESE
私は13日後にボードテストを受けています
BACK INTO ENGLISH
I am taking the board test after 13 days
INTO JAPANESE
私は13日後にボードテストを受けています
BACK INTO ENGLISH
I am taking the board test after 13 days
That didn't even make that much sense in English.