Hello dear, when I had choosen the major subject some years ago, I didn't think too much I just go with flow. I love to read about how machines and systems work? The science behind them and so I choose engineering. Why so much of worrying?
It is very obvious if someone is passionate about something,he/she will choose that instead of situation,circumstances.
Remember, one thing whatever you will do just do with faith. I mean to say, believe on your decision.
Second thing,all qualifications are equal. Third thing, put all your effort into that and whatever the major you choose,posses its higher position at your mind.