Hello Aspirant,

Hope you are doing great. By repeating the class 11th it doesn't actually effects the attempts of the JEE MAIN. The exam is conducted only after the 12th and after you attempt for the examination of board so it doesn't relate you to the 11th examination. After you qualify the 12th you can take the attempt and score good percentile accordingly with your preparation. And regards the IIT colleges they check only the score of JEE you have repeated or not doesn't  be actually considered. You just need to score well and also the basic eligibility to qualify the 12th.

All the best