I (girl, 15 years old) am not allowed out by myself. If my girl friends are doing something I have to say no or take my brother with me. What can I do?

You can try to talk to your parents.
Because: it is your right to do things by yourself.
There are children’s rights.
These rights apply to all children and young people in the entire world.
You can explain three of these rights to your parents.

You have the right to be treated equally!
That means: you must be treated just like your brother.
You have the right to free time and relaxation!
That means: you can also decide yourself what you do in your free time.
You have the right to privacy!
That means: you also need to have time to yourself and with your girl friends.

Maybe your parents are not listening to you.
Maybe you don’t have the confidence to talk about it with them.
In that case you can go to a help centre.
You can get advice here if you have problems.
The consultants here can talk to you together with your parents.
You can find a help centre here, for example:
http://www.bke.de/?SID=00F-6B8-FCB-4F5
If you enter your address you can find a centre close to you.