Even I am going to the astrophysics.But astrophysics or astrochemistry UG programmes are not available in India as there is not much scope for this field.However I have decided to take physics or mathematics as major in UG.After completion of undergraduation programme I will take astrophysics in PG programme along with integrated phd.So even you can follow my method.Take chemistry as you can get perfection in this field because astrochemistry is the branch of chemistry.