As Bodhisutra said, you need not worry about specialization now. After finishing the first year of MBA, you can develop a fair idea about it. However, reflecting on the following factors may help you make a decision.
1) Try to understand what area of management interests you. The indicators of interest are: Do you feel passionate about it? Or do you enjoy talking about it? Suppose you are passionate about marketing but hesitate to opt for it because you do not have good communication skills or you are an introvert. In that case, try to overcome those weaknesses to study what you love rather than opting for something that does not interest you much.
2) Understand that communication does not mean being talkative. It involves talking that makes sense and is meaningful. Skills like communication can be acquired through coaching, self-learning, and practice. Traits like shyness and introversion can be changed into assertiveness and extroversion by conscious efforts we make to change, helped by the environment that facilitates such change. For example, being with marketing professionals for some time, observing them, and receiving training from them can help you change these traits.
3) Gather enough data about the field of your interest to know about it in its entirety. For example, the subject of marketing may make someone conjure up images of people sweating in the field under the searing sun, canvassing the products. It is not merely about canvassing products; it also includes other areas of specialization like brand management, media management, or market analysis, which may interest you. Therefore, gather enough data about the field of your interest.
Hope this helps.
B. Saikumar