I am thinking...rather wondering

I have got into this mode where I am thinking about what makes people choose their profession (read course as in college/university). It is such an important decision of a person's life but I feel most people are not adequately equipped to make that decision. People around me (including myself), mostly follow what is in demand or what seems to be a sane choice according to elders and parents. It is not that they hate the subject and still do it because it is in demand, though on second thoughts, I think it might be the case for a few people.
For me, I had software engineering as the first choice because I thought I had the aptitude to write software. An idea formed due to some stupid programs written in the computer lab of our school. At that time though it seemed like an achievement. And another important factor was that I would get a good job. After all, most, if not all, software engineers get jobs in India. Yet another important factor was less struggle and easier life compared to some other professions like architecture, fashion, hotel management. All three of them were also on my mind at the time of decision making. But they lost the race due to the difficult life they entailed. And family members did not think the professions were good enough compared to engineer/doctor. Becoming a doctor was just out of reach for me, I was not so studious. So, software it is.
Do most people make this decision in a similar way? Calculated decision? Or do some people get an inner calling telling them what they are meant to do?
I feel at that young age, we do not know anything about how things are in different professions. This is especially true of people not living in metros. Sometimes I wonder what if we have made the wrong decision. There is no way to find out…at least for me. But at least I am happy that I am not bad at my job. My supervisors say I am quite good. He doesn't always say good things. But it is ok as long as he doesn't say only bad things ;) So maybe I can safely deduce that I made the right choice. Maybe it is all pre-decided up there and we just have an illusion that we made a choice, when it really wasn't a choice but it was destiny or our fate decided by God.