You Don't Have to Sign a Waiver
If police place a document like this in front of a young person, THEY / YOU DON'T HAVE TO SIGN IT! There is no law in Canada that says a young person must sign or initial ANY PART of a Waiver document.
Please note that the decision whether to sign or initial the Waiver belongs to the young person, not the parent. A parent who physically or verbally interferes with police could find themself in a lot of trouble and get hurt.
A Waiver means that you are giving up rights under the Youth Criminal Justice Act and the Charter of Rights. That's not a good idea for any young person who is about to answer police questions.
You don't have to sign or initial a document that says the police have told you about your rights. There is no legal requirement that says you have to sign or initial.
In the movies and on TV it seems that police always convince a person in their custody to talk. That doesn't mean it is a good idea for you. Just because police expect you to do it doesn't mean you must do it.
Of course, you should be polite to the police officer, and you should properly identify yourself, and you should not be abusive, but there is no law that says you must comply with a police request that you sign an acknowledgement or waiver of your rights or make a confession. There is no law that says you must fill out a form like the example below and enter your initials.
You can politely decline. "No, I don't wish to initial or sign that document."
At the end of your visit to the police detachment, following arrest, there may be a document called a "Promise to Appear" or an "Undertaking" or "Recognizance" related to your release from custody. You can sign that, but there is no advantage to you in signing anything else.
If the police are going to charge you anyway, there is no point in helping their cvase against you. If the police don't already have enough evidence to charge you, whatever you say may end up helping them to charge you.
Be polite. Ask for your parents. Ask to speak to a lawyer. Don't sign or initial the waiver.