Are all German numbers like that?

No, it gets more confusing the more numbers you add. 34563 4+30 thousand +500 3+60

Ow my brain.

You probably did, but then you did the sensible thing and (mostly) changed it around. You can read some 19th century novels and find stuff like “I am two and twenty years old”.

Mostly because it’s still the old order for the teens. 1616 could be read as sixteen hundred sixteen, right?

And that’s because the numbers we use today where originally brought to Europe by Arabs. Arabic is read right to left. So having reading numbers that way used to be the ‘correct’ way in lots of languages. German is just one of the few ones that stuck with it.