The first joke you land in a new language feels better than any grade.

Timing a joke in another language requires everything at once: the right word, the right moment, a sense of what the room finds funny. When it works, you have proof that you are not translating any more but actually in the language. No test result tells you that, which is why the feeling is out of proportion to the joke.

Aim at small funny things rather than correct sentences. Learn one bit of slang, one way people tease each other, one phrase that is only funny there. Say it badly a few times and wait for the laugh.