OLG

Update
New salary: 45K
Thanks everone!! I know it's very normal but much better ^ ^

First of all - I dont have any further advice for you.
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At least I can confirm this expectations. I would recommend to advance your German and get a B1 certificate (or similar) to proove your language skills.

Berlin is full of jobs with your skills and you could easily find a job for 20% more. A "start up" with 180 employees has enough money to pay proper salaries. The deal for a real start up is usually low salary but you get stocks. However this is your first job ... therefore I would ask for more as you described and if it is a "no" then start looking somewhere else and leave after another 6 months to have at least 1 year experience.

English language is a requirement in many large companies. And large companies are well known for nice salaries. You can receive courses for learning German there, too. 
English is used in startups as a second option. But they don't pay on the same level as global players.