CBSE 12th

You can do many things such as -
start your own business (for your information most successful businessman are less qualified than you).
continue studying (I recommend that you exercise this option) - If you want to study, please refer my answer to this post.If I got low marks in 12th less than 60% where should I go?
look for a job - search internet, I am sure you will find something
any combination of the above options: like (1 and 2), or (2 and 3) or (1 and 3).
All the best.
Do well in life (this is not the same as scoring well).

DU is a huge university which attracts a crowd of students with higher percentage. And also there is reservation for Delhi residents. So, chances are quite less but you can give it a shot.

You can prepare for Engineering entrance exams like JEE, BITSAT, ICAR, IPU-CET and others and score well in them to get into a good Engineering college and pursue your B.tech from there.
Or you can join B.sc in any government college and go for research and teaching as your career options.
There are other options but these are the broader options that people go for.

Hi,
There are no percentage needed in your class 10th and 12th to apply for Indian Airforce.
So, no need to worry about the percentage. You can directly apply for the NDA exam, which is conducted by the UPSC twice in a year.
Eligibility criteria:
The candidate should be complete +2 from a recognized state board of India.
Age limits is 16.5years to 19years.
Only unmarried male candidates are eligible.
Candidate should be physically fit.
So, if you fulfill above criteria then you have to apply NDA exam but in this no percentage restrictions.
For more details visit
www.upsc.gov.in
All the best.

Yes, you have a chance to get admission in this institute for doing architecture. It is a good institute in every term. So kindly apply for it.

Yes, there are many scholarship opportunity check NSP.

Hello Aditya,
You may refer the link below that gives the MHT-CET college predictor for the colleges that you may get with your marks:
https://www.shiksha.com/b-tech/resources/mhcet-college-predictor

Hello Vishal,
You may refer the link below that gives the college predictor for WBJEE:
https://www.shiksha.com/b-tech/resources/wbjee-college-predictor

Sorry to say, but JEE Advanced cutoff for different categories is:
General: 128
OBC: 115
Sc/St: 64
https://www.resonance.ac.in/reso/news/jee-advanced-branch-allotment.aspx
Check this branch and IIT college predictor.