If I am 38 percent German is that a lot?

Despite my having an ancient English last name, 3 of 4 of my grandparents had German last names and their ancestors came from Germany.  Not sure how many of my father's father's father had Germans in his line.  Can trace it back 9 generations into 16th Century English countryside so far, seems mostly English but I guess some Germans are in that line also.  I might be over 75% German.

So your 38 percent (about 3/8ths) shows 3 of your 8 great grandparents were of German lineage.

Well if you considere it is out of 100% you are 19/50ths German which is not that much

Probably means you're a European mongrel, like me.

38% is very roughly 62% lower than a full-blooded German.

German Americans are Americans who have full or partial German ancestry. With an estimated size of approximately 44.2 million in 2018, German Americans are the largest of the self-reported ancestry groups by the United States Census Bureau in its American Community Survey. German Americans account for about one third of the total ethnic German population in the world.

There's no such thing

maybe your (great)grandfather knocked up a few german lasses in the war, and the resulting babies all happened to take a DNA-socalled-ancestry test at the same  company you did

It is a lot if you had no idea of any German connection.   I am sure that your maths teacher will have told you that 38% is more than one third, nearly two fifths.

If you are in the USA, be aware that there was a lot of German immigration in the 19th and early 20th centuries.  Some mountain communities inland from the east coast speak a form of German, or did so until recently.

It's almost 40 percent!

No idea what further insight you think you can gain here.

Did you come up with Jewish too?

My gf was surprised to have both.

That's not enough to get you German citizenship, so no. Also, don't believe those ancestry DNA tests. They're bunk. There is no way to determine what it is they claim because, one, we don't have samples of ancient DNA and, two, people migrate constantly, so the only way such a test can say something like 38% is if it is a snapshot of some past date or ancient point in time, but what is that ancient point of time the said ancestry is supposed to have taken place? They always offer none because what they're suggesting they are providing you is IMPOSSIBLE.