Yes, you can definitely do an MA in the German Language after completing your BBA. However, if you are planning to finish the BBA program next year, I will advise you to start preparing for your application process immediately.

I have included some important requirements that might make your admission process a tad bit easier.

• A versatile academic profile with excellent scores 
• A good extracurricular background 
• Noteworthy internships 
• Some stellar Letters of Recommendation 
• A great Statement of Purpose 
• You will have to sit for entrance exams like GRE, IELTS, and TOEFL
• Last and most crucial is a German language certification

So you need to work on many things and only starting right away will make it possible for you to achieve your goal.