Hello,
From the information you shared in your question, it seems you may be a student in India or other country outside the U.S. The Education.com community is primarily focused on education and parenting in the United States. I suggest meeting with a guidance counselor or teachers at your school (or at the local college). They may have excellent insights to share with you, and will be able to ask you questions in person to help guide you in the right direction.
For general information about careers and college degrees, here are some resources on Education.com (again, focused on the U.S., but you may find some tips that apply for you too)...
Careers (includes job descriptions):
http://www.education.com/topic/teens-work/
Career Planning & Development:
http://www.education.com/topic/career-decisions-child/
High School - School & Academics articles (including what subjects to take to prepare for college):
http://www.education.com/grade/academic/high-school/
Thanks for asking!