It depends on how “German” the company is. If you can get an offer without knowing German, I assume 1. You don’t have to worry about language (English + Chinese should be enough) 2. You have certain skills that they require, this is basic for you.
Most “foreign” companies can be more organized than small Chinese offices, they will provide systematic training for new staff. If you are passionate to learn and work hard, there is nothing to worry about.
Other key factors…hmm. Be confident; be careful with details, maybe.