If it's Norwegian you want to learn, I think it's smarter to start learning Norwegian at once. Norwegians and Germans can't understand each other well. Also, german grammar is more difficult than Norwegian grammar. There are some Norwegian lessons on youtube, maybe those will help you?

My basic knowledge of German was very usefull when I started to learn swedish, since many of the grammatical structures which are very different from my mother tonge, are however common between those two languages. As said before , swedish and norwegian ar pretty close...but not the same.

Although they are related, they are separate languages. You might find learning Swedish or Danish might provide an easier introduction to Norwegian.