Hello aspirant, 

As your EWS rank is 18621 so there might be some chances that you get a seat in NIT but still you will not have much of the choice for branch selection.

You can use the college predictor tool to predict the best suited colleges for yourself. 

https://engineering.careers360.com/jee-main-college-predictor?icn=JEE_Main_clgpd&ici=JEE_Main_article_view_sticky

Also you can check this article to get a clear idea about the cutoffs of various colleges. 

https://www.google.com/amp/s/engineering.careers360.com/articles/jee-main-cutoff-for-top-nits/amp