First of all, if you have passed your 12th Std. examinations in the year 2019 then according to the eligibility criteria of JEE Advanced, you will not be able to appear for JEE Advanced 2021.

Also, If anyone wishes to pursue B.Tech at IIT Bombay, then the admission is purely based on the rank of the candidate in JEE Advanced exam and nothing else.

And one more thing, according to the eligibility criteria of JEE Advanced, one has to score at least 75 % marks in 12th Std. or has to be in the top 20 percentile of his respective board to appear for JEE Advanced.

If you want cutoffs of last years for the admission to various IITs, kindly use the following link:

https://josaa.nic.in/webinfocms/Public/View.aspx?page=71