If kids had their career choices picked for them at the age of 12 I think that it would be helpful, but also not a good idea. I think that getting their career choices picked for them by the age of 12 would be useful so that they didn't have to go through the struggle of trying to find a job in the future and everything is all set for them. If the kids had their jobs already chosen from their interests now it could really help them in the future.
The downside for having 12 year old's jobs getting chosen for them at the young age is not really a good idea because even if the jobs were based off their interests as kids that could always change in the future. Even if in the future them didn't have the same interests as their younger self they would be very miserable at their actual job.