you can finish your education (Ausbildung) even if your interview has a negative result.
You will have a status of tolerance untill your education is finished (Law: § 60a AufenthG).
If your education is closely followed by a job offer your tolerated status can be extended.
Detailed information see 'Netzwerk Berlin hilft' (Network Berlin helps): http://bit.ly/2bHj06d
(English translation by Google).
All the best for your interview!