Post #5- For some students yes and for some no. I do think some students are more set on a major going in than others as mathmom’s students demonstrate. I think a lot of kids say Engineering or medicine but either do not make it through the weed out classes or find a major they had never encountered or considered. A 17 year old is only exposed to so many options, a 20 year old a lot more and of course a 45 year old a ton more. What you major in still doesn’t seal your fate.
I’d say an engineering major has a higher chance of changing than a math major. I have no facts to back this up only anecdotes. But the kids I know weren’t really exposed to engineering before college. They were good STEM kids whose parents and teachers said- be an engineer. Once they saw real engineering (or st least the college version of it), they did not enjoy it.