JEE Main

Yes. Recently, the National Testing Agency which conducted the JEE Main (Jan & April attempts) released a public notice on 15 April stating that candidates can make correction in their category including Economically Weaker Sections (EWS) in their Online Application Form (Gen, OBC-NCL, SC, ST & EWS) from 15/04/2019 to 17/04/2019 (the latest by 5.00pm). Post this date no further chance will be given for correction. Students can visit the website for details and read the complete notice.

Yes dear. Don't worry. You will easily get admission in NITs, everything is matching according to your choice.

You can easily get any of the NIT in any of the stream you want at this score and under this reserved category quota, now you have to only choose the college in which you want to take admission.

Use JEE Mains college predictor. Enter your JEE Mains 2019 score or rank to predict the colleges.
https://www.shiksha.com/b-tech/resources/jee-mains-college-predictor

Hello Shreshth Gupta,
From this year onwards NTA would be announcing results based on percentile and not on raw marks. In addition, it is expected that about 3 lakh students will be cleared for JEE Advanced. In view of the foregoing, it can be safely stated that cut-off percentile could be 70.

No, you have to score at least 98 percentile.

With this score in JEE Mains, your chances of getting a reputed branch in HBTU are very less. You have April attempt left and you can increase your score in the April attempt to get HBTU.

Hello,
As only a month is left for the JEE Advanced exam, you should follow these preparation tips & strategies:
From now, don't study any new topic. Revise the ones you have studied. Stay updated with the latest notifications and news.
Focus on the most important topics of JEE Advanced exam. Make regular notes of the important stuff. This will help you in your last minute preparation. Solve previous years question papers and take online mock tests. This will give you an idea about the patter and difficulty level of the questions. Learn all the important formulas.
Best of luck.

At this score, getting CSE may limit your chances to get into the top colleges of the country, so I'll suggest you opt for any of the branches and then opt for internal up-gradation of the branch.

Getting COEP for B.Tech. in Civil Engineering at this score might be difficult as this college has very high cutoff but you can try may be in the last round you can get this branch and college.