Don' worry! This is not the issue, It will not affect to appear JEE Main Entrance Exam. Focus on your exam preparation to score a good marks in the exam. You can prefer the below given article for your exam preparation.

https://engineering.careers360.com/articles/jee-main-preparation-tips

Good Luck!

Dear Ayush, 

You should be careful when filling credentials. Well in this case it won't matter. Major things to be taken care of are your name and your parents name otherwise there are chances of papers getting mixed up. According to me in this situation this mistake won't affect your result. But in future just be extae careful because such forms are very important.