Guess what's in my mind

Let's play a game of guessing X, the rule is this:
\- I will think of a X, but I will keep it as a secret in my mind;
\- You will do the guessing by asking me any question, except for directly asking what X in my mind is;
\- You will ask me question one at a time, and I shall answer with "yes", "no", "maybe";
\- You shall prefix each question with its index number (starting from 1);
\- You can ask me up to N questions, if you can guess the correct answer before you use up all your questions, you win; otherwise you lose.
\- You shall continue asking me questions until you win or lose.