For me about English, the first time that I could understand someone in English I was like "wow". I was super excited, though I couldn't understand all of the words they were using but I could get what they mean.
This happened again when I could text to someone and they could understand what I mean, then when I could watch English movies with English subtitles and then without subtitles.
And a couple of days ago when I could finish a book that I could easily understand, I felt that excitement again.
But I know that I haven't passed all the stages of fluency yet. I think I will call myself fluent the day that I make the minimum number of mistakes (like a native) and I can easily talk and write about my deep feelings and complex thoughts.
For me to be fluent means that I can express myself easily in a given language about any topic and that I can read, without any difficulty, any literature book or essay (concerning my professional activity).
I do not care too much about grammar and writing.
I don't have the abilities to be