Hey,

The competition is increasing day by day in everything. So it's better to start preparing as soon as possible. If you will start now you will be having ample of time to practice the syllabus and questions that will give you an edge over your competitor.

There are many books available, but for Quantitative aptitude you can read QUANTITATIVE APTITUDE BY RS AGARWAL or RD SHARMA  CLASS 11 &12th.

For verbal ability you can read Norman Lewis English Vocabulary or read newspapers, online articles, etc.

All the very best

Thank you.