In the case of your child, because both you and your child have successfully applied for the Canadian citizenship, and you are going to attend the citizenship ceremony and take the oath, therefore, both you and your child will become Canadian citizen, even if your child does not want to be a Canadian citizen now.
Who attends the citizenship ceremony Adults and children aged 14 or over must attend the citizenship ceremony and take the oath.
Parents receive certificates of citizenship for their children under age 14. These children do not have to attend, but they are welcome. http://www.cic.gc.ca/english/citizenship/cit-ceremony.asp