As a class 12th student, it is normal that you have a very limited knowledge of different fields in engineering.
Out of 8 semesters, the first 2 are the same for all branches at BITS. During these 2 semesters you’ll be taught one fundamental course from each branch and some engineering mathematics. In the 7th and 8th semester, you’ll choose open electives from your branch or other branches.
Now as for placements, you can choose some CS courses as your open electives during your ECE, which will help you for IT placements. Even though at present, people tend to focus only on CSE, the demand for ECE will rise in the coming years due to increasing growth in IOT, Smart sensors, Robotics and Communication systems.
Here are the important courses from both these branches-
You can research a bit and then decide which branch will suit you the best. Overall, both these branches are really good, and you’ll have an amazing time at BITS Hyderabad.