I think it isn't too late until you actually start your 1st year classes to decide on your 2nd year specialization.
Here are things you should consider:
1) Your school reputation - your school might attract recruiters from specific fields/industry due to your school curriculum strength, etc. If you want to get a great job after graduating, you should research this.
2) Popular Specializations - i.e. Finance, Strategy, General Management etc. Finance MBAs are always in demand. One can pursue many opportunities with Finance MBA on their resume. One can argue the same thing with specilizations in GM, Strategy, Accounting etc.
3) Sample the classes during your 1st year - usually you will take specialization classes in your second year. See which courses interest you the most during your first year and decide.
4) Visit School Career Services Center - Your school Career Services Office should offer various tests that can tell your personality type and based on the test results - they can lead you to various career options that might be suitable for you.
5) Consult Others - talk to fellow students, faculty members, alums etc. Latest trend/demand in certain industry can change a lot of things. For example, in the late 1990's - one couldn't find a seat in CIS/MIS courses due to internet boom in many business schools.
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