I'm going with the rest of my five-person core family and being joined by four cousins. We'll be taking an airline none of us have taken before and who's service and safety record I know nothing of. Some people we meet will speak English, but some of our German relatives we'll be visiting only know German, and only I and my mother know much German, and she much more than I. Mom's also the only person with experience of EU laws and customs. Should I be worried?
I went to Germany on a school trip when I was 14 but stayed at a home- stay by myself, who spoke no English for 3 weeks. I had never been away from my parents/home for an extensive period of time and it was scary but I loved it. The language barrier can be difficult but you will have help from your family and in my experience Germans are normally patient and will try and help you, but try to have Google translate or a phrasebook because even keywords can get the message through. Germany is not a third world country so generally safety standards are fine but if in doubt do some research. Likewise I don't think there are that many crazy customs in Germany and if you don't understand people will help you and not judge you because you are foreign, again research if you are unsure. Overall relax, smile, be friendly to the locals and they will reciprocate and have an amazing time. :)
Why not ask them to come with you to help you translate things. You mustn't panic on things like this. Why not find a family member who is fluent in both and they can come with you. Trust me you've got nothing to lose, my friend, by embarking on a trip like this.
As for that, go online and search for the airline you're talking about. You ought to do that. Do that, and if you think that airline isn't good, find another.