BCA

Without filling application form you can not get admission in any college.

Yes, it is a little bit tough for you.

Check the below link for BCA colleges in U. P. You can filter the result based on location, accreditation, and ranking-
https://www.shiksha.com/it-software/colleges/bca-colleges-Uttar-Pradesh.

Candidates with Bachelor's degree (minimum of three years duration) or equivalent from a recognised university are eligible to apply. At the time of applying, candidates studying in three-year degree programmes should have passed all subjects from first to fourth semesters; while candidates studying

Dear,
B.Tech CSE/IT is a better choice as Indian Industry (IT) prefer them more than BCA/MCA. They are offered better package and bulk of them are recruited through campusing every year.

I can understand the situation you have now. If you just passed your 12th and you don't have any idea about where your interest is, just take a break and you can go with preparation for the various entrance examinations. If you want a short time decision, do Google about whatever comes in your mind.

Yes you can change from IGNOU to Amity and if you want to do BCA the good option will be Amity.

If you really interested in the field of civil engineering then go for polytechnic because, if you go 11th and 12th further you need to learn each and everything (I guess you are able to understand what I mean). If you do your Diploma, you will be thorough with your basics of civil engineering, whic

Computer hardware:
Computer hardware is the physical body of the computer system.I don't think that in India any institute rum program for computer hardware seperately.you need to be join the bachelor of computer applications in any college or university.
Search for that and apply.