I am in class 7 I am quite confused about what to do on growing up, as a career
Everyone says I am good at art and I should become an artist
My friends also say that I should opt my career related to sports especially dance
My English I better than my peers, should take up something related to english
My family encourages me to become a doctor as everyone in my family is a doc( but they never discourage me of any other career )
I am greatly interested in physics and thinking to become an automobile engineer( many discourage me saying that its not a career for girls)
Or should I opt for something related to computers and IT
To help- I easily except challenges I never mug up I understand things faster than some children
What to do...

If you could make a living doing your passion that would be the best for you. You most likely will be working 30 to 40 years of your life and it makes it a lot easier if you like what you do. Maybe when you get into high school you will join some clubs and this may help you pick a career, or help you eliminate some. You have time so relax a little bit. It looks like you are very good in many fields, so maybe you should be researching them. I love art and I am stay at home mom, but I have gotten things published in art magazines. Kids in high school here have written articles in our area newspapers. Try doing some of this in your area, in school and talk to your teachers, they are most likely willing and would love to help you. Good Luck in your future!

Since you have such a wide variety of choices, why don't you do some elimination. To do that, why not create and pros and cons list of all those jobs that you listed. Do some more thorough research in each job to have a more comprehensive pros and cons list. Try that first.