difference between Kota education and class 11 and 12 school and take admission in dummy school . I I'm going to Kota for jee preparation then It will impact on my board exam

Hello,
Their will not be any problem if you are joining dummy school,just that you would require little bit of more dedication,and maintain schedule such that you can prepare for both boards as well jee exam.
I have seen many students joining such way and excelling in both just that be motivated and keep practicing long answers of boards too.

So it solely depends on you, follow all the guidelines provided by your parents and teachers and you will surely excel.
Hope that helps;