HELLO,

If you have written your roll number correctly and later shaded the correct bubbles as instructed by your teacher or invigilator ,then your OMR sheet will not be rejected.

TRB will consider the final , correctly shaded bubbles for evaluation and your minor mistakes like you have shaded the wrong bubble first will not be treated as disqualification if you have corrected them properly on the same sheet and since the invigilator has allowed you to correct it then your OMR sheet is mostly correct.

Hope this help!