Dear Student,

Its great that you wish to gain prior knowledge. First of all , you don't require any computer skills beforehand. Everything is taught in the college.

But if you still want to use your free time, then it would be best to learn C /C++programming and learn using arduino/raspberry pie. I assure you that this fill help you throughout your college life and make you one step ahead of others.If you want to learn more, you can learn data structures in C/C++ or learn python too.

Hope my answer helps.

All the best for your future.