Dear aspirant....!!

After 12th(Science stream) you will have to opt for the Entrance Exams and post that only you can join Engineering colleges in India.

If your marks are not good(and you are keen on doing Engineering) then you can opt for Diploma courses in Polytechnics. As you have done 12th, your 1st year (of 3 year diploma course) will be waived. After diploma you can opt for direct admission to Degree Colleges (No Entrance Tests required). As you would have Diploma by then your 1st Year (of 4 year Engineering course) will be waived.

So Basically if you join diploma:-

1. After 12th:- 12th + 2 years Diploma + 3 years Engineering.

All the best....!!