If you don't have interest in a particular field go for Computer Science. It is a very good branch for girls (as compared to mechanical where you have to do some heavy stuff) , also the placements are very good. A lot will depend on your JEE rank so study hard if you want to get your desired branch.
What ever field of engineering interest you most. If you want to create specimens and study and obaerve, become a bioengineer, there are several fields of engineering.
chemical engineering is the best........I am a chemical engineer still my answer is unbiased
