If you have been summoned to court, the date setting a time limit for which to respond is printed on the notice. If you cannot find it, contact the clerk of the court and ask.
Yes, you may write these things down, but you may not read them aloud in court. You may refer to your notes, but you must usually ask for permission to read anything that you are entering into the record, and reading your entire defense would not be permissible. Study your notes, summarize them, and anticipate what the other side might try to argue. If need be, attend a court case and see what goes on. That way, you will be less nervous about the situation.