I find it dubious someone can just decide to be a "software engineer". You'd have to already have a personal interest in programming and be doing it on your own as a hobby. Are there people who seriously just go to college for 4 years and learn coding like accounting and then just do a 9-5 job? There are thousands of decent hackers out there, maybe just uptrain.
There are lots of people who just went to college for four years and then got jobs writing code. I didn't keep a track of many of them but none of the ones I know of turned out to be good at it.
Curiously, it seems to be mostly women who are good devs and yet didn't start until college. I'm not really sure what to make of that. Could be selection bias - since boys are encouraged to play with computers, most of the ones who will be any good at it started in grade school, while since girls have no such encouragement, even ones that are good at it may never have discovered that until college. Or it could be that all boys who are good at computers let it take over their life, and girls have many competing interests. Or it could that only girls have the discipline to become good at something without it becoming their life.