Hey Sakshi,

You are elligible for applying in IISER because your 12th marks is more than 85%(it may vary).

There are too many caretaria and exams to take admission in IISC and IISER.

For IISER you have to qualify JEE advance. The competition is tough.

Here are the last year cutoff:

2015-Jee Adv rank-8500

2916-Jee Adv rank-6500

2017-Jee adv rank-5800

Best of Luck!