Hello Aditya,
If you think that you can crack IITs or NITs only then go for Engineering. Because private colleges are not good for engineering.
If you have gift of gab and good at GK, then law will best for you. In recent few years, There is slower growth in engineering than Law.
It will be better if you crack CLAT. Through this exam, you can get admission in top Law College in India.

Note- for engineering, Maths physics, Chemistry these three must be good not only maths. For IIT JEE Mains you have to score good in all subjects.
Good Luck.