Thanks for your intro, it's great to have you here... and very nice to meet someone that has been born in Germany (like yours truly LOL) - you should find plenty to nourish your interest here - there are a variety of groups to choose from, so take your time and explore (note that without a patronship/subscription you can choose one group only).
For your particular interests, you might have a closer look at The Wanderings of the Tribes, dealing with the migrations of the various Germanic peoples, or at Theudokuntho, dedicated to the early Germanics. And there is so much more...

Frið!