I enjoy practicing English like you. I am not sure what my level in English is , but I am not a beginner for sure. With regard to where I studied English, I spent one year studying English in the US. It was a beautiful year in my life
Let me correct your language as you requested. There are a few mistakes you made. For example, you wrote " It is been a long time" the correct is " it (has) been a long time " and " ?Do you consider yourself intermediate who has a great number of vocabulary, but has difficulty using complex grammar" this question, it does not make sense for me. Also, " Are a beginner " it should be " (is) a beginner"
.However, your language is awesome. you should not be worried about your mistakes, even native speakers make mistakes in their own language