Your own disobedience in the past will not ultimately keep your child from becoming a believer. It is pointless to berate yourself for any wrong behavior on your part as if it were the reason your child is without Christ. This does not mean that we as parents should not repent and do better, and even admit wrong to our children. But the reason your child is without Christ is related to his or her own sin. Every parent is sinful and inconsistent. This has never been a barrier to God if He desires to save your child. Illustrations abound of children who come from far less godly families who are nonetheless converted to Christ. In fact, this may have been the case in your own experience.