JEE Main

Your NTA score is 20.8 means your estimate rank is above 5 Lacs, so it's very unlikely for you to get admission in NIT, until you are from ST category, but you can go for a private college that accepts on the basis of 12th class or management quota.

A 79 percentile convert to a rank between 2,10,000 to 2,40,000. So you can go for private college and several college affiliated with mumbai university.

College like vishwakarma institute of information technology ( VIIT), Pimpri Chinchwad college of engineering etc.

Dayananda Sagar University (DSU) provides the BTech programme to students who wish to pursue a career in Engineering and Technology. The admissions are based on the entrace test method. The prominent entrance exams include KCET, JEE Main, COMEDK UGET, Uni-GAUGE, DSAT, among others. Hence, students can appear for any of these various exams and apply for their favorite BTech programme at DSU.

With a 65.92 percentile ranking in JEE Main, you stand a chance to get into some mid-level government engineering colleges in Maharashtra through All India Quota. Some of them are:

Konkan Gyanpeeth College of Engineering, Karjat – offers Mechanical and Civil branches among others.

Priyadarshini College of Engineering, Nagpur – has good reputation for infrastructure and variety of branches.

St. John College of Engineering, Thane – slightly higher cutoff, but possible in later CAP rounds.Located in Pune, VJTI Mumbai and VNIT Nagpur are also Top tier government colleges but they are out of reach at this pecentile.

JEE Mains is not fixed and can change from one attempt to another.

The January and April sessions may have different difficulty levels and a different number of students.

So, even if a student gets the same marks in both attempts, the percentile might be slightly different.

This happens because percentile is calculated based on how many students scored less than you in that session.

The process remains the same, but the result can vary depending on overall performance.

With a percentile of 51 in JEE MAIN if you are thinking of to get admission in Walchand Institute of Technology, Solapur then I must say that it's quite hard to get admission with that low score through general quota. You may try via MHT-CET, reserved category or management quota if eligible 

You can apply for state-level colleges, and if you have reservations, then also apply for another government college. Consider appearing for state-level engineering entrance exams, as they might have different eligibility criteria and cutoffs.

If you get 63 % and belong to sc category u have great chance to apply NIITs, IITs and GFTIs Consider exploring options like NIT agartala, meghalaya raipur Jalandhar, and Goa, as well as IIITs like Allahabad and Gwalior you can also explore GFTIs u can also considering private universities like SRM LPU  Chandigarh University.