Hey! I am really glad to see that you are so determined at such a yoing age Good going!
Step 1 - Options in Class 11
First things first. You need to opt for Biology, Physics, Chemistry in class 11, 12.
Step 2 - MBBS
With a PCB background, you need to start preparing for MBBS entrance exams. You must complete the MBBS degree from a recognized college and complete compulsory internship.
Step 3 - MS
MBBS is graduation, completing that you will need to go for Post Graduation. Complete MS (Master of Surgery) from a recognized college / University.
PS : This thread is open to suggestions. Anyone here who is a practicing doctor, or studying in similar field is requested to give inputs!