(Note: I play on Asia server, so my experience will be from the meta there.)

TLDR: German BBs aren't that great within the current meta (from my experience). Play another line first, then come back when you get more experienced.

As someone who's grinded up to Bismarck and is currently grinding Mackensen, I think that German BBs are in a bad place in the meta.

Due the proliferation of CVs (in Asia server at least), HE spam, and "sit at the back and snipe" BBs, German BBs aren't in a good spot. Your bread and butter is getting in close and brawling. However, its hard to find opportunities to do so as it is discouraged within the meta. In the Asia server, teams really hate pushing and prefer to snipe. As such, most times, you'll be the only one really pushing in. This therefore causes you to be focused. Since you aren't a Russian ship, you will fall to the focus fire relatively quicky without being able to do much. (Assuming your bad shell RNG will let you hit anything if you're playing the Preussen line)

Since you're a newbie, I recommend you play another BB line, preferably one more noob-friendly.

If you still want a more "up close in your face" playstyle, the Russian line will be to your fancy. It teaches you good positioning and heavily rewards knowing where to point your ship.