Dear @Amayta,
Welcome to the Wefugees Community and thank you for reaching out to us.
We actually discussed a very similar question here before. A child is not able to obtain an independent permanent residence permit under the age of 16 years. As soon as they have reached the minimum age, they may apply under these conditions (exemplary for Berlin).
I hope this helps and please don't hesitate to get back to us with any further question.
All the best,
Meike