She Thinks She Is Good

She always thinks that she is good in study. She told me she understood what teacher teaches in class and she knows how to do all the home works. So she does not have to do revision when exam period. I admitted that I am a lazy mother therefore I did not force her to do revision. However, I am kind of regretting after saw her test paper. She has few wrong answer in the test paper and I think she really not understand the question. I should guide her more...haii