I'd actually assumed you were already studying at university for a degree. If you already have the necessary qualification to do so then my recommendation would be to go to university and to continue making your game in your spare time.
I already have an "Abitur", which is a degree that allows me to go to university or start a job training
You're still missing a proven track record and industry experience, and even with both of these things many teams fail.
Do you think that's enough or is there still something missing to convince the viewers to back some money or at least share the campaign with friends who may invest some money in the game?
To reiterate my earlier suggestion, why not continue your studies (with the new aim of attending and completing university) AND continue working on your game?