Careers advice is still a thing, but presumably the point is that most such meetings start with you telling the adviser the sort of thing you are interested in, and they will advise you based on that. So the inspiration still has to be there, and that can start from a very young age. I am not quite in the place I imagined I'd be when I was 11, but I'm very close to it, and even when I was a few years younger than that I was clearly already on this path.
Of course, it's hard to understand what started me out on my journey -- if I really had to pin it down to one moment then I'd owe it to reading Hawking's book "The Universe in a Nutshell" some time in the first few months of my first year at High School -- and equally it's hard to understand what, if anything, led to me not considering anything other than this. But everything children watch, see, hear and do can be a factor in determining what they set out to become, and it's presumably beneficial to everyone to make the choices on offer as wide as possible.