I am not good enough in dance (which i always thought is my passion)?

You are still very young as anyone of any age can practice and master the art of dancing. Learning to dance at a formal school is a very long term process and if you go back regularly you will find that you will significantly improve. No one starts out good because the human body isn't capable of creating arbitrary motions with perfect coordination on the first attempt (it is always a process of teaching your muscles the 'feel' of motions by repetition). No one can master an art without practice and patience and if you find passion in something you will be able to find the will to follow through with it no matter what. Never compare yourself to people who have been dancing in a studio for a while, but consider how if you go to that studio you can be as good and even better than them with time.