Be sure of your calling.
BBA,Doctor and Agriculture have their own aura and they cannot be compared on any particular scale. Your future depends on your hard work and dedication.Make sure you are chooding a course you are really passionate learning about and then you will make your way through it.
After BBA you may go for MBA which opens your way towards a well-settled career where you can earn a lot or you may go for  Finance Sector, Human Resources,Real Estate Agents and so on.But keep one thing in mind you can only excell in this field if you have the required skills and that zeal to explore more.
Now coming to Medical field.Being a doctor is a matter of great deal in our society because of the status a doctor enjoys and the money that he ears for one thing quite obvious is that diseases can't go off this planet no matter what and thanks to the 'pollution' that is increasing day by day. To be a doctor you need to do MBBS which is not easy and requires lot of patience but it really does vouch for a well-settled career if you have the required skills to cure a patient.
Now coming to Agriculture field,you know that the economy of our country depends on Agriculture and we really need good quality seeds and other such related things to make agriculture flourish,so there is so much for you to explore and discover in this field.You can become the Agriculture officer or researcher.
So better take up a course that drives your interests the most and work hard with perseverance and you will get all the success.
Good luck.