Dear Anitha rank depend upon many factors, first, you have a decent score in 10+2. According to the last year trends I analysis that if you have 90% in 10+2 and you get 120 out of 180 then a high chance of getting rank below 5000 but its very uncertain because of increasing competition in every year and number of student appears in every year,so my advice is to try to get higher marks as possible but must be more than 110 marks.

All the best Anitha