Hello Aspirant,

With 120 score in JEE MAINS you are eligible to appear JEE ADVANCE.

As per the eligibility criteria for JEE ADVANCE on the basis of JEE MAINS -

The candidates who qualified JEE MAINS and are in the top 2,50,000 candidates on the basis of merit are eligible for appearing

Please check this article you will find it helpful

https://engineering.careers360.com/exams/jee-advanced

Hope this will help.

Thank You