At one point or the other, during our first lesson, or subsequent ones, my students assess their own level. They feel confident, so to speak!, that their accent is awful, their knowledge of vocabulary wanting, and their conjugations weak. Incredibly, some of them announce all this with a broad smile etched across their face.
What I invariably say, at that point, is:
you are not the best person to assess your own level. It's the job of the language teacher, not the student's!
I have yet to come across a student who doesn't underestimate his/her level. Everyone thinks, wrongly, that their level is lower, even when they've reached an advanced level!
and, in any case, except for exam preparation, language learning is not about levels, nor perfect sentences, but rather about expressing oneself as accurately as possible.
Of course, grammar and simplified books all have levels, but I don't spend any time telling my student which level is theirs.
I want them to focus on creating the conditions to immerse themselves in the language by practising all four skills equally, not on evaluations. The former means experiencing the language from the inside, the latter means they're always slightly on the outside, judging their performance and themselves.
90% of my work is psychology, because confidence is what students lack and need the most to express themselves in a foreign language.
The minute they assess their own level, is the minute they focus on what is lacking, as opposed to what they already know. Never has the 'glass half-full' metaphor been more apt than with language learning!
If you're thinking of learning a foreign language, focus on the reason(s) why you want to learn it, on your motivation. This will carry you further than you ever thought possible, because you will focus on how to use the language, not on how people will judge you for it.
Don't hesitate to send me your questions.