Hello Sumaiya, it is not necessary to appear for JEE advance, even if you are eligible for this.  It's only depend on you. Her advance is a entrance exam which is held for admission in IIT. so if you are not that much interested in our,  and you are happy with NIT or any other good engineering college, then it is not mandatory to give exam.

I hope it will help you more.

Thanks. 

Hello dear!!!! No it is not necessary to appear for JEE advance after you have appeared for JEE mains. You can only appear in JEE advanced if you have qualified your JEE mains and you have been able to get the marks required to appear in JEE advanced. Only after qualifying JEE advanced, you can get IITs. Otherwise after qualifying mains you have options for NITs IIITs and other engineering colleges.