As a rule, you cannot become a Norwegian citizen by notification if you are under the age of 18. There are two exceptions to this rule:
1. You can become a Norwegian citizen automatically if your parents are Nordic citizens and become Norwegian citizens by notification
If you are resident in Norway and your parents become Norwegian citizens by notification, you will also automatically become a Norwegian citizen. It does not matter what country/countries your are a citizen of.
You will not automatically become a Norwegian citizen if you are married or a registered partner when your parents submit notification of Norwegian citizenship.
2. You can become a Norwegian citizen by notification if you have previously been a Norwegian citizen