Hello Ritesh,
Ask yourself where you want to see in next 10-15 years and then decide.If you are interested in both mechanical and management.Then,do btech in mechanical and then get your mba dregree from reputed college.But having interest and doing the work for the rest are two different thing so choose wisely.And it is not compulsory to have MBA degree to start business.You can start your business with any management degree.If you grasp technical things fast then choose btech or you grasp managerial concepts fast then choose bba.
Hope I cleared your doubt.All the best for future endeavour!!!

I understand your point and believe i can answer your problem as i myself am from mechanical bakground. See, the basic point is, B.tech and BBA are 2 different career options which run parallely.In mechanical engineering, you have deal with real life scenarios dealing with production,manufacturing,mechanics and so on.While in BBA, you need to learn how to do business and strategies involved in those. In fact, if you want a suggestion from my side, that would be to pursue B.tech in Mechanical engineering first and then pursue MBA in the desired branch you want.

Hello Ritesh!

First do your self analysis that whether you really like Mechanical line and BBA both with same interest level.

Look, Mechanical line will be having fields like MACHINE DESIGNING, MANUFACTURING ENGINEERING, PRODUCTION ENGINEERING, AUTOMOBILE ENGINEERING, ROBOTICS , etc.

You will have to deal with lots of geometrical designs in ENGINEERING DRAWING.

Even after knowing the subjects and fields of MECHANICAL LINE, you are interested in it then you can do B.tech in Mechanical Engineering and after completion of your graduation you can opt for MBA as well.

You can switch from Engineering to Business field but you can't switch from Business to Engineering field. That's the beauty of Engineering.

All the best!!!