Hi Vivek,

First of all congratulations for following this endeavour! Hee are some of the guidelines you can use:

• A bachelors degree in  focused on Physics, Chemistry, Mathematics, Biology, Aerospace Engineering or Physical Sciences. 
• Post graduation, aspirants need to complete a Ph.D. in Astrophysics, Geophysics or Metaphysics. At this point, the candidate will get to specialize in a certain stream. Once the Ph.D. is complete, aspirants need to take an entrance test for which there are two options –

1.      Clearing the ‘Joint Entrance Exam’ help by the IITs through which one can join ISRO

2.      Clearing the entrance exam held by NASA for the recruitment of scientists and astronauts

Check this link for for more info and list of collges:

https://www.shiksha.com/aviation/articles/career-as-an-astronaut-blogId-809