is doing MBA after finishingengineering is good?

The top MBA programs want you to have three to five years work experience. There is a huge difference between an MBA you can get after your BS in engineering and one from a top school.

As for specialization — at the top programs, it is better to get a general degree if you aren’t sure what interests you. Many engineers choose to go into finance or consulting

To me, it all depends on your career plans after finishing your engineering degree. If you intend to work in a corporate sector or banks for instance, having an MBA is definitely good. But if you intend to become a specialist, then you’d better take up post grad in engineering itself.