Excellent choice. Software is a leading trend and i wish you all the best here.
On what you should study, for now stick to what is taught in School. When you progress to +1+2(or PUC), you will learn C and C++. Since software engineer is the field you are looking for try to understand the WHY's in programming. Try to explore languages like Python , Ruby etc. There is a concept called data structures- Learn and be good on this as you progress and you will be golden. :-)