Although, many students start their gate preparation from 2nd year onward but You have sufficient time for gate preparation.
Gate syllabus is revised every year by its organizing institute. Gate exam is conducted by any one of the iits every year. This year it is conducted by IIT Roorkee. It also provides its syllabus for this year in every branch.
Paper consists of 3 parts:General Aptitude , Technical, Engineering Mathematics.
1st paper consists technical questions which is realted to your respective branch.
You can get more information from: “http://gate.iitr.ernet.in/wp-ontent/uploads/2016/07/Syllabi_GATE2017.pdf”
All the best.