I'm in the UK, so I can't say how applicable my advice is to German (and other countries') university systems.
With that in mind, I would say that you shouldn't do a degree in education. Do a degree in another subject and then you can take a teaching course afterwards if you still want to be a teacher. It keeps your options open for longer and if you ultimately decide that your fears over teaching as a career aren't worth the job, you'll have plenty of other paths open to you. I'd also recommend getting work experience in teaching (most schools would be happy for the help, I imagine; try asking ones that you haven't been a student at) to see if it's a good choice for you.
It's also not your parents' business what career you want to do, but that's not to say you should disregard their advice (they do have your best interests at heart, after all). Don't disregard anyone's advice, really; ask teachers, family and universities for help.
I'm not sure how it works in Germany, but you can get a degree in Chemistry or Bio and then get your teaching certificate (that's basically how it works in the US, unless you're studying something specific like art education or special education).
Do what makes you happy, not your parents. Sure, their opinion may matter a lot right now while you live under their roof, but when you go off to university and live your own life, you'll either be happy with your decision of following your dreams, or you'll regret your decision if you follow their dreams.
I commend you for studying the sciences, because there seems to be a decline in people that are motivated enough to go through with it. I was in a similar situation as you, but it was that my parents wanted me to be an engineer (because I'm really good at math and science), but I chose to study design (and after my parents actually saw my work, they put a lot of faith and trust in my decision). I am so much happier studying design because even though I'm good at academic courses, I just wouldn't be happy feeling like I'm doing homework for the rest of my life.
One of my good friends is a history and english teacher at a local high school and has her Masters in both areas. Sure she doesn't make as much money as her banker friends, but she's very happy where she is and the money doesn't matter as much.
Well, if you really like Chemistry and Biology, go for it. Maybe, to keep things a little broader, don't go into the teaching course right away, it should be possible to switch between Chemistry (Chemie) and Chemistry for teaching (Chemie auf Lehramt). If you get the chance to go for open days at university, go and ask questions. Really.
Oh, and sometimes it is nice to go study a little further away than the next town. Not only because the course might be better, but also because it directly takes you out of your environment.
That sounds like a really great suggestion. I'm actually in Munich and I'm pretty sure LMU and TUM are the some best Universities in Germany, but I'll see. LMU has a open day for chemistry in March so I'll definately go there. Thank you very much for your help
Oh, keep in mind you need a doctorate at least if you want to go into research in Chemistry. You don't need that long of studies for teaching. Another thing with studying teaching in Germany: try to study in the Land you want to teach in. It's difficult to switch afterwards. That's what you get with the system of decentralised schools...