thank you for sharing your question with us and I am sorry for the light delay. As for your question:
After the three years they might prolong your Aufenthaltstitel for 3 years or 5 years.
Depending on the integration you have accomplished at that time, for example if you work, have started an Ausbildung, if you have reached high language skills etc.
I hope this could help you, if you have further questions please do not hesitate to contact our community.