hi,asailaja

im sorry that you cannot enter into IIST with jee mains only.the candidates must clear jee advanced exam.you can check it out through this link:

• https://engineering.careers360.com/articles/iist-btech-admission

for jee advanced:

Age Limit – General category candidates should have been born on or after October 1, 1994. Relaxation of 5 years is provided to the candidates belonging to SC/ST/PwD category.

• https://engineering.careers360.com/exams/jee-advanced
• https://www.iist.ac.in/admissions/undergraduate

all the best!!

note:if any links available,copy and paste it in the url bar of your webpage.

I Hope this information will be useful to you.

if you need additional information,let us know to help you.

Thank you!!!:)