IIM does not provide 3 years bba program. Only the iim rohtak and iim indore provides the integrated five year bba-mba course.

The eligibility to apply for integrated bba - Mba program at iim is -

Qualification - Minimum 60% marks in SSC and minimmum 60 % marks in hsc for general category candidate.

Age - Maximum 20 years of age as on July 31, 2020

So you are eligible to apply for integrated bba-mba course at iim if you follow the age criteria.

For getting admission to integrated bba -mba program you have to fill application or registration form. Than you have to appear in a entrance test  i.e  Ipmat exam. Candidates after clearing IPMAT exam will be called for Personal Interview and

Written Ability Test. Based on personal interview, impat score ,written ability test and Past Academics admission will be given to the candidates.

Hope it helps.