Hey Nitin,

There is no problem if you have a gap of almost two years after your 12th for any entrance exam until and unless it asks for as particular eligibility related to age or 12th year like in JEE, most of the entrance exam eligibility says that you must have passed 12th examinations and you must have minimum 17 years of age

You just have to submit a gap year certificate or Gap year affidavit when taking admission into any college after a gap period between 12th and University's admission.

Good Luck!