I don't think that's a problem in this case, the article says she was 16, and it's legal to work at 16.
In the UK it's legal to work below 16, but you can only be employed legally for a limited amount of hours. Self-employment doesn't have those restrictions, and you don't pay taxes either (until you turn 16).
I wonder how much money she made with that afterwards as it seems not to be doing so well now.
wait I never heard of that, I know the girl you are talking about, but I never heard that particular story, anyone have a link?
I would just keep this sort of detail (her age) as quiet as possible, if I was her.