I think that passion is something that you can put into anything you do, like a sort of energy. People are flexible and they grow a lot during their lifespan. What you are passionate about when you are 15 years old may be something you're not passionate about when you're 20 years old - and that is ok! It's perfectly normal to have an interest and a hobby for a while and then change your mind and do something else. 

This idea of choosing "one thing" for the rest of your life is a strange concept that has been created somewhere. Don't put so much pressure on yourself to "find your one passion". Enjoy your life! Enjoy learning new things and discovering new opportunities. Your passions will unfold as you get older and your experiences start to merge together. 

In the meantime, make life your passion and enjoy the process.

Well the good thing is you have your whole life ahead of you. It takes time to figure out what you are actually good at, and what makes you tick.

The best thing you can do is to sit down and write about what you want to do...it's a start! 

Oh please, don't do that. Don't depend of what other people think, you need think by yourself. You have a talent, everybody have a talent. Think, use your intelligence, what do you really like to do? Maybe write stories, or make cakes, I don't know. Use your brain!
Don't be slave of what people think, think by yourself.

It' s not possible you haven't got any passion. To find out what's your real passion, try to imagine doing something every day the whole day. Now if you think this wouldn't be boring, you've found your passion. A passion is something that helps you living better.

Passion is impulsive and catchy in some way. it comes ups and downs as often as not. Perhaps you know not too much about yourself to be aware what your real passion is at present because of your knowledge and view. My suggestion is you may try as much as you can while you are young and have enough time to explore yourself. After that, you may say what your real passion is. Travel is a good manner to explore what your passion is and what work you are going for in the following decades.

Good luck to your explore and tell us what your passion is indeed.