Upgrading your branch after the first year is not an easy task. Although upgrading to civil will be easier as compared to other branches like CSE and ECE. Nevertheless, the only thing you need is a really good CGPA which is probably 9.5 or above to be on the safer side. And the grading for individual subjects is relative, so you will have to be amongst the toppers in your batch.
So, if you have a strong desire for up-gradation, then you will have to really get down to study and avoid major club activities for the first year particularly.