Sir J.J College of Architecture Mumbai Answered Questions

First visit this link to check B.Arch colleges based upon your rank:
https://www.shiksha.com/b-tech/resources/jee-mains-college-predictor?utm_source=connect&utm_medium=CR_JEECP&utm_campaign=6919840
Then visit this link for various colleges which provides you brochure:
https://www.shiksha.com/architecture-planning/colleges/b-arch-colleges-india

Admission in Sir J. J. College of Architecture, Mumbai has been started, you can apply now for the same. And According to the eligibility criteria admission of the candidate is through counselling, based on marks obtained in 10+2/ Diploma and score obtained in National Aptitude Test in Architecture NATA. Requirements are: 10+2/ Diploma marks - 50%, NATA score - 50%.

There are very few seats for general in both the colleges. Also, in NIT, minimum board percentage should be 75%, so you will not get NIT.
For Sir JJ, the admissions are through 50% board + 50% your competitive scores. Your board percentage seems less, so the chances are very thin.

The admission for B. Arch 2018 batch has already started you may apply for the same. It can be done on both the basis offline and online.
For eligibility criteria and other information you may go through the link below:
https://www-shiksha-com.cdn.ampproject.org/v/s/www.shiksha.com/architecture-planning/course/amp/b-arch-sir-j-j-college-of-architecture-mumbai-71170?amp_js_v=a1&_gsa=1&usqp=mq331AQCCAE=#amp_tf=From %1$s&share=https://www.shiksha.com/architecture-planning/course/amp/b-arch-sir-j-j-college-of-architecture-mumbai-71170#amp_tf=From %1$s

Sir JJ College of Architecture is one of the most sought-after colleges not only in Maharashtra but across the country.
Unfortunately, the number of seats for a general candidate is very less. if you are a male candidate it's even worse.
The admission process is through the DTE website and the only other college that competes in this process is Rachna Sansad AOA.
So, for any hopes in admission as a general candidate, you need to have a rank under 30 hoping that a lot of people before you choose Rachna Sansad.
To achieve that Rank you need to obtain an aggregate of 150+ which is calculated by considering 50%of your NATA score + board percentile.
I know it seems difficult but best of luck:D

Admission is through counselling conducted by Directorate of Technical Education, Maharashtra based on marks obtained in 10+2/ Diploma and score obtained in National Aptitude Test in Architecture(NATA).
Selection parameter and weightages:
10+2/ Diploma marks - 50%
NATA score - 50%

Please check for your eligibility to secure a seat in B.Arch. at Sir J.J College of Architecture from the criteria mentioned at the link provided below:
https://www.shiksha.com/architecture-planning/course/b-arch-sir-j-j-college-of-architecture-mumbai-71170

I am enlisting top colleges with their fee structure:
Centre For Environmental Planning & TechnologyAhmedabad-1,61,000
Lovely Professional University - 19500
Jadavpur UniversityKolkata-2,730
School of Planning & Architecture Delhi-46,300
NIMS UniversityJaipur-1,11,000
Sir J. College Of ArchitectureMumbai-17,800
Indian Institute of TechnologyKharagpur-74,000
National Institute of TechnologyThiruchirapalli-39,400
Jamia Millia Islamia New Delhi-64,500
Manipal UniversityManipal-3,04,000