It is very difficult to predict your rank/ percentile which you can get with a marks of  120

Because, The Percentile/rank is not constant with marks, it keeps on changing every year depending upon various factors like number of students appeared for the exam, the kind of marks they had  obtained , the toughness level of the exam for different shifts etc.

But yes by following the previous year's trends then,
120 marks will be around 97 in ppercentilewhich means you have got a rank of around 30,000

You can also go through he link which is provided below

https://engineering.careers360.com/articles/jee-main-marks-vs-percentile

For knowing about the colleges which you may get with the marks you have mentioned here you can go through the link below.

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

Hope this helped, Thank you .