Hi there!!!!! No,dropping a year wouldn't affect your eligibility criteria for jee. You can check out more info for eligibility criteria for jee mains using the following link:

https://engineering.careers360.com/articles/jee-main-eligibility-criteria

You can also check jee advanced eligibility criteria using the following link: https://engineering.careers360.com/articles/jee-advanced-eligibility-criteria/amp

Hope this answers your query.