The choice of a branch is dependent on your interest. If you prefer to be a mechanical engineer,

then yes, sure go for it. CVRU Bihar (http://www.cvrubihar.ac.in) has a very good B.Tech course for you if you consider it.

If you have failed in your 1st year, then you can reappear for the examination in terms of supplementary examination. So you didn't need to change your college. Now if you want to change your stream or if you are eager to change your college then yeah! you can change it but for that you have to reappear for the entrances again and having the valid score can only provide you admission to the courses.

To know more about ME as a career visit the link below:

https://www.careers360.com/courses/mechanical-engineering-course

I hope this answer helps. All the very best for your future endeavors!