Adults and some minors must have been physically present in Canada for at least 1095 days during the five years right before the date you sign your application.
IRCC encourages you to apply with more than 1095 days of physical presence to have extra days in case there is a problem with the calculation.
Use a travel journal to help record your trips outside Canada. It will help you calculate your physical presence in Canada.
Regardless of your age, if required under the Income Tax Act, you must meet your personal income tax filing obligations in three tax years that are fully or partially within the five years right before the date you apply.