sir, i have passed matriculation in 2011 and 12th in 2013 if i repeat my 12th in 2015 will i be eligible for jee advance 2015.....or any other way to be eligible..? plz help

No. you are not eligible for jee 2015.

No, you will not be eligible if you repeat in 2015. You are eligible for JEE in the same year when you complete your board and the next consecutive year. So, you are eligible to give it in 2013 and 2014.
Thanks