Over 40 at least you are almost halfway. Definitely you can switch, if you are a half decent thinker, most things are possible; I am sure you can become an electrician and that, at least where I live, makes very good money. Plumbers you cannot find if you are keedeep in your own poop here. In my home country my old classmates (I have an electrician degree but became a software engineer) are making more than most programmers being electricians. Not sure what is wrong with someone who cannot flip burgers after 40.