Hi, After 12th you can plan your bachelors in physics, astronomy, maths or chemistry even. So after doing Bsc you can do masters in astronomy and later PhD. The Phd and even masters will include your specialization in areas like star formation, planet studies and cosmology. there are many more.
After phD you shall get a post doc at a university or a research institute and which will help you to gain a lot of experience and knowledge.
then you have your own setup or be called as professional astrologer. Hope this helps. Good Luck.