The only area of human endeavor in which zeal and enthusiasm are accepted substitutes for knowledge, skill, and experience is sex.
You should feel free to post questions, answers, comments, or whatever else you like. The only caveat is that you need to be okay with having someone come along behind you and correct any places where you may have given a bum answer on something and not let it hurt your feelings or discourage you.
If you wait until you don't make mistakes yourself anymore before you start answering questions, you'll never get to answer a question.