Hello,

After 12th you can join for engineering in CSE branch and learn the basic subjects to deal with computer science world. This way you can understand everything about the Computer World. If you want to do robotics then you have to do a course for that or else you will get it in final year semesters. By that time you will get no time to implement the ideas. So in the first year learn basic programming and a course in robotics will do the work and you can start implementing your ideas.

there are many free websited available which provides free course for robotics. you don't have to pay money for that.

Hope it helps!