First of all you should choose your interest over money because once you earn money but you don't like your job then it will be of no use to earn money.after class 12th there are many opportunities for you almost all opportunities are open since your mathematics as well as biology in your class 12th.

The most additional option for you is to become a doctor aur engineer and this gives you a lot of money based on your skills like doctors earn really huge amount of money if there surgeon for masters.engineering you can go for computer science and engineering if you want to earn more money because now a days scope is very high and companies are offering really good salary. These are the two most rewarding sectors after that you can go for trading and management jobs which will be possible only after your masters specifically in management.