Hello Nitin, I think so that you can give neet exam 2021 while studying in some private college and if you get selected in government college or any top college then off course you can leave that college and take admission in later one.

If you are not satisfied with your college and the kind of knowledge you are receiving , then it makes sense to quit and look for the better option.

P.S.-  some colleges have a bond where it is mentioned that you have pay certain amount if you leave college after period of 30 days.

Good luck for your future