Hey

Since you have given your 12th board exams from Karnataka you will be eligible to apply for the domicile in Karnataka provided that you have a reason to show why you were not present in the state for 7 consequtive years. The acceptable reasons include being achild of an employee of the Union Government or an employee of the Union or Karnataka State Government( Undertaking or Joint Sector Undertaking), who is liable to be transferred anywhere in India as per the terms and conditions of his employment and has worked in Karnataka for a minimum period of one year.

The full details of all the clauses that can get you a domicile of Karnataka are present on https://azimpremjiuniversity.edu.in/SitePages/pdf/eligibility-clauses-for-karnataka-domicile.pdf

Incase you still have any difficulty I insist you to go to the nearest Taluk

All the best!