Problem Speaking Mother Language?

Ok, so let's start with some language learning theory. There are two stages that you go through when acquiring proficiency in a new language: the passive and the active stage. During the passive stage you will learn the grammar, build up your vocabulary and gradually get to a point where you can understand texts and speeches. This is the first stage you go through when learning a language. It is followed by the active stage, the stage where you will finally activate all the grammar and vocabulary you memorized so that you can actively use them for writing and speaking. This stage is much harder to get to than the passive stage, so it will take a while.

I am a student of Japanese language and for me the activation of the active skill was also a struggle. Here are some things that helped me: When you are out and see a billboard or something like that, try to think of the German words for the text on it. If you can't, try to look it up when you get home. I used to carry a small notebook to write down words or grammar points I wasn't sure of. When you are by yourself, talk to yourself in German. Or, if you have a pet, talk to your pet. My cat has gotten used to my Japanese mumblings by now. You don't have to make complex sentences in the beginning, just start with really simple things like "I am hungry" or "I should get going". This will build up your confidence and you will gradually start trying to say more difficult things. Don't worry too much if you are not sure about the grammar or words you used - speak it out and then, if you have the time, look up whether it was correct. Repeat the correct sentence again and make sure to use it several times more.

One more useful thing you can do is a technique called "shadowing". Listen to a speech on TEDTalks or youtube in German that you understand quite well. Put on headphones. Repeat every sentence after the speaker, preferably without having to stop the video. It will give you a better feel for the pronounciation and flow of the language. Also, try singing along to German songs, if you know any.

Lastly, I am sure your mother would not be disappointed in your German skills. It is a difficult language (I should know, I am German) and if you grew up in an English-speaking country it is only natural that your first language is English. Try talking to your mother in German, tell her you would like to improve and ask her to correct your pronounciation and grammar when you talk to her. She will be glad to help you. You have a native speaker in your family - take advantage of that!